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tag:theconversation.com,2011:/fr/topics/flowers-7413/articles Flowers – The Conversation 2020-11-23T19:03:09Z tag:theconversation.com,2011:article/148920 2020-11-23T19:03:09Z 2020-11-23T19:03:09Z Silky oaks are older than dinosaurs and literally drip nectar – but watch out for the cyanide

  Shutterstock

As we come to the end of spring, look up from the footpath or at the park, and you may spot the fiery flowers of the silky oak, Grevillea robusta.

You may already be familiar with grevilleas – perhaps you have low- growing ground cover and shrub species in your garden.

Some people love the brilliant red, yellow, orange or white flowers of grevilleas. They're also nesting and roosting havens for small native birds, and so people may plant them to attract wildlife.

Of all the grevillias, the silky oak is the one that catches my eye. It's the largest and tallest of the species, reaching up to 30 metres. They're now blooming along the east coast and in some inland places – like huge orange light bulbs dominating the skyline.

 <img alt="A bird feeding on silky oak flower" src="https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370727/original/file-20201123-17-1n2zq6s.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Silky oaks flowers are a magnet for birds and insects. Shutterstock

Strong like oak

Grevilleas have an ancestry older than dinosaurs. They originated on the super-continent Gondwana, and are closely related to banksias, waratahs and proteas.

Today, the 360 species of grevilleas occur in Indonesia and Australia and are a diverse group. Their colourful, distinctive flowers lack petals and instead consist of a long tube known as a "calyx", which splits into four "lobes".

   Read more: Spring is here and wattles are out in bloom: a love letter to our iconic flowers

Like most other grevillea, silky oak possesses proteoid or cluster roots, which are dense and fine. These roots greatly increase the absorbing surface area and allow plants to thrive in nutrient-deprived soils.

The word "robusta" refers to the fact that the timber is strong like real oak. The freshly split wood has a silky texture, and a pattern and light colour resembling English oak – hence the common name "silky oak".

 <img alt="Silky oak timber" src="https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370729/original/file-20201123-13-4i08av.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Grevillia robusta has a silky texture when split for timber. Shutterstock

Watch out for the cyanide

Grevilleas literally drip nectar, much to the delight of native birds and bees. Aboriginal people enjoyed the sweet nectar straight from the plant or mixed with water — the original lolly water.

But you have to know which species to taste as some, including the silky oak, contain hydrogen cyanide that could make you ill.

Like other grevilleas the silky oak also contains tridecyl resorcinol, which causes an allergic reaction leading to contact dermatitis. The chemical is similar to the toxicodendron in poison ivy.

So when working with silky oaks, you'd be wise to wear gloves, a face mask, protective eye wear (or face shield) and long sleeved clothing. Washing hands and showering at the end of the day is also recommended.

 <img alt="gardening gloves" src="https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370731/original/file-20201123-23-1h5hjjr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Wear gardening gloves when handling silky oak, just to be one the safe side. Shutterstock

A prized timber

Silky oak timber was widely used in colonial times. Then it was marketed as "lacewood", and that name persists today among some who use it.

Silky oak veneer was used widely in colonial table tops and other furniture. Over the years, silky oak has also been used to make window frames because it is resistant to wood rot.

Overseas, silky oak timber is still widely grown, in timber plantations and as windbreaks.

   Read more: Here are 5 practical ways trees can help us survive climate change

But it's not widely available in Australia, due to low market demand – the allergens and cyanide it contains means people are generally reluctant to work with it. However silky oak is still highly prized by those who make guitars, and wood turners who make bowls and cabinets.

 <img alt="Painted silky oak window frames" src="https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/370732/original/file-20201123-21-17f79g0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Silky oak timber is rot-resistant and was often used in window frames. Shutterstock

In the garden

Although an evergreen tree, some specimens are almost semi-deciduous, losing most of their foliage just prior to flowering.

Some specimens of silky oak can be a bit scraggly in their canopy form. They can benefit enormously from a bit of formative pruning when they are young, and perhaps some structural pruning from a good arborist as they get older. A little attention at the right time will be amply rewarded with a safe and great looking tree that can live for 150 years or more.

Silky oak is drought-tolerant. In dry times they often flower a bit later than their usual October blooming, providing a big splash of colour in otherwise drab and difficult years.

The trees can be vulnerable to frost when young, but grow well once taller. This makes the silky oak a potential winner as climate change brings warmer, drier weather.

Silky oaks have been declared an environmental weed in parts of New South Wales and Victoria where it grows outside its native distribution range. They're also considered an invasive or invader plant in Hawaii and South Africa. However Grevillea robusta is declining in its natural rainforest/wet forest habitat.

In some cities in China, silky oaks have been planted along roadsides with great success. The tree has also gained the Royal Horticultural Society's Award of Garden Merit for its performance in growing under United Kingdom conditions. That just shows you how one person's weed is another's treasure.

   Read more: The river red gum is an icon of the driest continent

Gregory Moore does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
 Silky oaks, or Grevillea robusta, are in bloom. These hardy, attractive trees light up the sky in late spring – but handle with care. Gregory Moore, Doctor of Botany, University of Melbourne Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/146109 2020-09-29T20:01:34Z 2020-09-29T20:01:34Z Spring is here and wattles are out in bloom: a love letter to our iconic flowers

  Shutterstock

Spring has arrived, and all over the country the hills and riversides are burnished with the green and gold of Australian wattles, all belonging to the genus Acacia.

It's a spectacular sight, but not a surprising one as there are about 1,000 Australian species in the Acacia genus ranging from very small shrubs to tall, longed-lived trees. They occur in ecosystems from the arid inland to the wet forests of the east coast.

   À lire aussi : Tree ferns are older than dinosaurs. And that's not even the most interesting thing about them

Wattles have been widely used by Indigenous people for millenia, and celebrated by "Wattle Day" on September 1 for more than a century.

But their lineage may be much older. Australian wattles have relatives in Africa, South America, India and parts of Southeast Asia. This distribution suggests the wattles may have originated in Gondwana before the super-continent fragmented about 180 million years ago.

So let's take a closer look at what makes these iconic flowers so special.

 <img alt="Wattle on a cloudy day" src="https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/359954/original/file-20200925-20-90ckdc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Wattle can always brighten a dreary day. Shutterstock

Don't blame wattles for your hay fever

Not everyone welcomes the wattles' golden blooms — many blame wattle pollen for their hay fever or asthma.

However, many species of wattle have aggregated pollen, which means it's very heavy and tends to fall straight to ground. You have to be virtually under the plant for it to affect you.

They can cause trouble, but it's more likely your allergy is due to some other inconspicuous plant, such as grass, that you haven't noticed compared to the bright yellow of the wattles. It's worth having an allergy test.

   À lire aussi : How to manage grass pollen exposure this hay fever season: an expert guide

While a majority of wattles flower in spring and summer, a significant group — such as the sunshine wattle (A. botrycephala), Gawler Range wattle (A. iteaphylla) and flax wattle (A linifolia) — flowers in autumn and winter. This can give the impression in some places that they're flowering year-round.

What's more, many species are hardy, and they can help in the process of taking nitrogen from the air and adding to the soil. That means they can be very handy in ancient, nutrient-poor Australian soils.

 <img alt="A mulga in the Australian desert" src="https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=521&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=521&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=521&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=654&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=654&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360472/original/file-20200929-14-1r2142v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=654&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Mulga grows over about 20% of our continent. Mark Marathon/Wikimedia, CC BY-SA

Many of the smaller shrub wattles may live for only a decade or so, but some, such as mulga (Acacia aneura) can live for centuries and are crucial to the viability and stability of arid inland ecosystems. They can have surprisingly large and deep root systems for such small shrubs or trees. This is to obtain water, but also binds the soil.

However, mulga-munching horses, cattle and other feral grazers threaten the persistence of mulga-dominated communities. If mulga and other inland Acacia species are lost, the soils can become loose and mobile, which results in stable productive land becoming desert.

By any other name

In the early 2000s, there was fierce debate among plant taxonomists about how closely the African and Australian species were related.

The name "Acacia" rightly belonged to the African group, but because there were so many Australian species that would need to be renamed, Australia was allowed to keep the name "Acacia" in 2011 — much to the chagrin of foreign taxonomists.

This resulted in the genus being divided. Australian wattles stayed as Acacia, but African wattles are now in the genera Vachellia or Senegalia, and those from the middle Americas (around Mexico) are Acaciella and Mariosousa.

The different names reflect long, separate histories and different ecological characteristics. (The name changes rankle still with taxonomists!)

 <img alt="Close-up of black wattle flowers" src="https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360467/original/file-20200929-22-65x56c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Black wattle is a pest overseas. Shutterstock

There are also weedy wattles in Australia and elsewhere. Many of us know from hard experience that the splendid ornamental tree, Cootamundra wattle (Acacia baileyiana), can become a weed if it grows outside its very restricted natural range in New South Wales. And Australia's black wattle (A. mearnsii) is a significant weed in other parts of the world.

It can come as a bit of a blow to know Australia's floral emblem, golden wattle (A. pycnantha), can be weedy both at home and when it travels abroad (perhaps like some Australians).

   À lire aussi : The black wattle is a boon for Australians (and a pest everywhere else)

Interestingly, most of the Australian wattles lack thorns, unlike their relatives in Africa. In Africa, thorns protect the plants from large mammalian grazers such as giraffes.

Ants love wattles, too

If you don't like ants, it might be worth checking which species of wattle you have in your backyard, or intend to buy.

Many wattles have a very special relationship with some insects. In Central America, ants penetrate the thorns of Bulls Horn wattle trees and establish their colonies. They then defend the tree against other insects, and if branches of another tree touch the host tree, the ants will cause such damage that the other tree will die back.

 <img alt="" src="https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/360464/original/file-20200929-20-dftc3q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 There are more than 1,000 species of wattle in the Acacia genus. Shutterstock

In Australia, the relationship between ants and wattles is based on food. The hard wattle seeds have a tasty and oil-rich outgrowth called an "aril", which is irresistible to some ant species.

The ants harvest the seeds and take them back to their nest, where they're safe from other hungry grazers until it is damaged by fire or flood and the seeds germinate.

   À lire aussi : Why tiny ants have invaded your house, and what to do about it

Some wattles, the mulga among them, have little glands at the base of their phyllodes (the modified leaf stalks). These glands secrete a form of sugary syrup that attracts feeding ants. These ants may also protect host trees or perhaps leave the flowers alone to allow a greater seed set to grow.

It's clear wattles have a lot going for them. They are diverse in number, habit, size, longevity and flowering season — there's a wattle for every occasion. For all of these great traits, it's still that green and gold that endears them to Australians.

Gregory Moore ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 With their vibrant blooms and a lineage tracing back to the ancient supercontinent of Gondwana, wattles have a lot going for them. Gregory Moore, Doctor of Botany, University of Melbourne Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/138162 2020-05-08T12:17:36Z 2020-05-08T12:17:36Z The flowers you buy your mom for Mother's Day may be tied to the US war on drugs

Colombia is the world's second-biggest cut flower exporter.  AP Photo/Fernando Vergara

What does Mother's Day flowers have to do with cocaine?

Very little, most people would think. But as an economist, I often explain to my students that the world is economically connected, often in strange ways. The flower business is one of those strange economic connections.

Mother's Day, which this year falls on May 10, is typically big for the American floral industry, which depends on it for over a quarter of all holiday flower sales. It's especially important to flower vendors this year as the coronavirus has ravaged the industry, affecting both supply and demand.

About a third of cut flowers purchased in the U.S. come from California, while the rest are imported. About 80% of those come from Colombia or Ecuador.

The story of how both countries became such an important source of flowers for the U.S. can be traced back to the U.S. war on drugs.

In the late 2000s, the U.S. and Colombian government were looking for new ways to stem the flow of cocaine into the U.S. Part of the strategy involved law enforcement: increasing interdictions to stop drugs before they crossed the border and ramping up arrests of people selling drugs in the U.S.

Another part of this strategy, however, was to convince farmers in Colombia to stop growing coca leaves, a traditional Andean plant that provides the raw ingredient for making cocaine, by giving them preferential access to U.S. markets if they grow something else.

The goal of the program was to give these subsistence farmers a legal crop that would be roughly as profitable as growing coca leaves – whether flowers, honey or coffee. This is formally called crop substitution.

In theory, by cutting back the supply of coca leaves, the price of the key raw material in cocaine rises. This cost increase is passed along the supply chain, raising the price of cocaine at every point.

Why is raising the price of cocaine important? A basic idea in economics is the "law of demand," which says the higher the price of a product the less people buy, holding everything else constant. Pushing up the price of cocaine should reduce the amount Americans consume.

Not just Colombia but also Ecuador, Bolivia and Peru – all coca-producing countries – get duty-free access to U.S. markets in exchange for clamping down on illegal drugs, under the Andean Trade Promotion and Drug Eradication Act.

Has crop substitution worked?

Well, not to eradicate the cocaine market. Only last year Colombia had a record coca crop, and the street price of cocaine hasn't budged. There are complicated reasons for this, including the persistence of U.S. demand for drugs, regardless of source, the ingenuity of drug trafficking organizations, and the cultural significance of coca leaf in the Andean region.

But this failed U.S. drug policy did lead to a surge in cut flower exports to the U.S. from both Colombia and Ecuador. Colombia exported US$800 million worth of flowers to the U.S. in 2019, up from $350 million in 2000. Ecuador's exports tripled from $90 million in 2000 to $270 million in 2019. As a result of the increased supply, flower prices in the U.S. rose less than average inflation.

So if you do manage to find flowers this Mother's Day, both your mom and the farmers who grow them will thank you for it.

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Jay L. Zagorsky does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
 A program intended to reduce coca production ended up giving two Latin American countries a big boost to their flower power. Jay L. Zagorsky, Senior Lecturer, Questrom School of Business, Boston University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/112755 2019-09-11T12:17:02Z 2019-09-11T12:17:02Z In dandelions and fireflies, artists try to make sense of climate change

Visitors walk through Japanese artist Yayoi Kusama's installation 'Fireflies on the Water.' maurizio mucciola/flickr, CC BY-NC-ND

Climate change is real, it's accelerating and it's terrifying. We are adding carbon to the atmosphere at a rate 100 times faster than any previous natural increases, such as those that occurred at the end of the last ice age.

The effects are easily made visible through dramatic images of rapidly shrinking glaciers or the Amazon rainforest on fire.

But pictures like these can distance us from environmental catastrophe, turning it into something spectacular, arresting – even paralyzing. They don't communicate the everyday impact of climate change, which is also taking place in our own backyards.

In the book I'm currently writing, I've made these smaller, less obvious effects my focus. I explore the work of artists and poets who help us understand how the smallest changes to the environment can signal large-scale damage.

They build on a crucial legacy left by Victorian observers of the natural world who emphasized the need to pay careful attention to the tiny details of our surroundings.

Observant Victorians

No one was more insistent on the importance of looking closely at the ordinary and the everyday than the 19th-century art critic and social thinker John Ruskin.

 <img alt="" src="https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=873&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=873&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=873&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1097&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1097&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291638/original/file-20190909-109957-za45hz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1097&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 John Everett Millais' 1853 portrait of Ruskin. Ashmolean Museum

His advice to "go to Nature … rejecting nothing, selecting nothing and scorning nothing" inspired many artists of the era – British artists like John Everett Millais and John Brett, and American painters John Henry Hill and William Trost Richards.

Meanwhile, books and articles, such as J.G. Wood's "Common Objects of the Country" and Anne Wright's "The Observing Eye," popularized scientific observation as a practice available to all, teaching people to find wonder in the world about them – in "the sky, the leaves and pebbles," as Ruskin wrote.

Many contemporary artists have picked up the baton, showing how three very ordinary species from the natural world – dandelions, fireflies and lichens – can stimulate our imagination and make us think about climate change in new ways.

The resilience of dandelions

Few plants are more ubiquitous than the dandelion.

In the 19th century, its yellow flowers and decorative fluffy seed-heads often appeared in sentimental paintings of children gathering dandelions in meadows or of young women blowing on gossamer puff-balls. They flourished in nursery rhyme illustrations and on decorative tiles.

 <img alt="" src="https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=351&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=351&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=351&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=441&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=441&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291641/original/file-20190909-109923-od9hii.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=441&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Dandelions dotted the landscapes of 19th-century children's picture books. New York Public Library

The flower was useful in the kitchen, too: Victorians ate it in salads and drank it in teas.

But at some point in the 19th century, its status morphed. Dandelions became a weed.

As all gardeners know, they are persistent. Weedkillers like sodium arsenite were introduced in the late 19th century. After World War II, powerful chemicals were developed for lawn maintenance, doing far more damage to people and the environment than dandelion roots. Gardening websites are still full of references to "the war on dandelions."

Today, British artist Edward Chell wants us to think about the damage done to these exiled weeds. He picks dandelions and other wild flowers on Britain's motorway verges – micro-habitats choking with pollutants that nonetheless sustain diverse vegetation.

 <img alt="" src="https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=775&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=775&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=775&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=974&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=974&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291645/original/file-20190909-109957-shqu0g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=974&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Edward Chell's 'Dandelion Taraxacum officinale: Road Dust M4.' Edward Chell, 2011. Road dust on 400gsm acid free watercolour/drawing paper 135 x 105 cm.

Using a silhouette drawing technique borrowed from the late 18th century, he draws the plant in outline and fills it with a mixture of ink and dust taken from the motorway. His images show the beautiful fragility of roadside weeds. But they're also records of toxicity, made with the residue of the internal combustion engine: unburned hydrocarbons, carbon monoxide, nitrogen oxides and particulate matter.

The jagged edges of the dandelion have a starring role in his series. But for Chell, the flower no longer symbolizes sentimentality and innocence, as it did in the Victorian era; instead, it's mutated into a chilling commentary on roadside pollution.

The magic of fireflies

In a threatened world, nature exerts a nostalgic pull. For many Americans, thoughts of fireflies transport them to the long, warm summer evenings of childhood.

Fireflies enjoy a double life: By day, they are unremarkable, dull-brown insects; by night, they are captivating sparks that dance together.

Victorian writers and artists saw magic in these floating dots of light, comparing them to fairies and goblins. The firefly's grip on the imagination was so strong that it inspired scientists to search for ways to explain the mysteries of bioluminescence.

The magic of fireflies persists. Japanese artist Yayoi Kusama has constructed several firefly installations that were inspired by a Japanese folktale about an old man in a field who was robbed on a pilgrimage. In Japanese culture, fireflies stand for the soul: In the tale, thousands of fireflies attack the man's assailants after his death.

The Phoenix Art Museum features one of Kusama's installations. Visitors can stand in a pitch-black room of mirror-lined walls, polished black granite floor and a black plexiglass ceiling, from which 250 LED lights hang and flicker like fireflies on a continuous two-and-a-half minute loop.

Yayoi Kusama's 'Infinity Mirror Room' at the Phoenix Art Museum.

To stand here is to experience infinity. It recalls the extraordinary beauty, yet fragility, of our natural environment.

And then you might wonder: When did I last see fireflies?

Fireflies have become increasingly uncommon – victims of habitat loss, pesticides and light pollution. Kusama's project, involving so many dancing electric dots of light, may be understood as a deeply ironic one.

The sagacity of lichen

It's not just artists who give significance to the small and overlooked.

Art historians can direct our attention to something we take for granted.

Mid-Victorian paintings are best known for their depictions of modern life, for dramatizing the personal side of historical events and for introducing us to stunning landscapes.

 <img alt="" src="https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=924&fit=crop&dpr=1 600w, https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=924&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=924&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1161&fit=crop&dpr=1 754w, https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1161&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/291646/original/file-20190909-109935-up3ck0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1161&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 John Everett Millais' 1852 painting 'A Huguenot on St Bartholomew's Day Refusing to Shield Himself from Danger by Wearing the Roman Catholic Badge.' Manson and Woods, Ltd.

But I suggest viewers concentrate on the apparently insignificant in these works; examine and think about the lichen that clings to rocks, tree trunks and walls in paintings like Millais' "A Huguenot" or Brett's "Val d'Aosta."

The very lichen that was painted in the mid-19th century likely contained traces of the substances that would destroy it.

For lichen is – as the Victorians came to realize – a bellwether for a polluted climate. Too much pollution near a big industrial city, and it disappears from tree trunks and stones.

Because of its quiet beauty and its vulnerability to environmental change, lichen has become a powerful symbol for fabric artists, poets and installation artists.

Yet lichen is the consummate survivor. It appears quickly after nuclear disaster or on newly solidified lava. What's more, lichen possesses properties – collaboration, determination, endurance – that humans will need to survive climate change.

"We are all lichens now," wrote eco-scholar Donna Haraway, referring to the symbiosis and codependence that characterizes lichen – and that increasingly will come to define the human experience.

Looking at 19th-century depictions of nature doesn't just lead to a nostalgic lamentation of all that's been lost.

Instead, it inspires us to try to grapple with the present – and spurs us to intervene in our future.

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Kate Flint does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
 Images of wildfires are powerful, but can make climate catastrophe seem like something spectacular and distant. So some artists are focusing on the plants and bugs in our immediate surroundings. Kate Flint, Provost Professor of Art History and English, USC Dornsife College of Letters, Arts and Sciences Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/119256 2019-06-25T19:05:24Z 2019-06-25T19:05:24Z Climate change: bees are disorientated by flowers' changing scents

Climate change is altering the smell of rosemary, affecting its quality and quantity Grégoire Lannoy/Flickr

Coffee, apples, honey – were it not for the precious work of pollinators, countless things that we eat and drink would not exist, totalling more than 30% of global food production. Most pollinators are insects, particularly from the bee family (close to a thousand species in France alone), along with butterflies and diptera, such as syrphids.

Apart from helping feed humans, these insects also play a vital role in the reproduction of a wide variety of wild plants, fertilising them by transporting pollen from one flower to another. This results in fruit and seed production. In this way, they contribute indirectly to dairy production through pasture renewal, and help sustain terrestrial ecosystems by supporting the first level of the food chain – plants.

Of course, pollinators do not provide these services selflessly: they search for their own food, nectar and pollen, that they collect from flowers. In their quest for these resources, they use their senses of sight and smell, identifying the density, colour and scent of flowers.

Yet like many other insects, pollinator populations are declining: over the past 30 years in the United Kingdom, a third of wild species have experienced a decrease in their area of occupancy. The rarest wild species are particularly at risk, due to the disappearance of their habitat.

Pollinators are also under threat from agricultural intensification and climate change. One way in which climate change could affect their pollination activity is connected to smell: climate change alters the scent of plants, and thus the capacity of bees to recognize them and orient themselves.

The memory of scent

 <img alt="" src="https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=578&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=578&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=578&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=726&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=726&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278677/original/file-20190610-52748-gz05ku.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=726&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 The back legs and side of the abdomen of this wild bee are covered in rosemary pollen. Coline Jaworski, CC BY-NC-ND

In their search for food, pollinators rely on visual signals (the colour and number of flowers) as well as olfactory cues – that is, floral scent. A bee is able to remember a fragrance and associate it with the resources provided by a given plant. Using memory, it is even capable of distinguishing between the scents of plants that produce high- or low-sugar nectar, and flowers that do not contain any nectar at all.

Floral scent consists of hundreds of small molecules emitted by the plant. However, when a plant is stressed (for example, owing to a lack of water or because it has been attacked by herbivores), it responds by emitting defensive compounds that alter its scent. A case in point is the smell of cut grass after mowing the lawn. The strong smell of rosemary – whose flowers have a similar fragrance, but with sweeter notes – is intended to protect the plant, and bees have learned to use it for finding nectar.

Climate change, which in many regions increases the risk of drought and rising temperatures, causes stress in plants, affecting their floral scent. In the Mediterranean basin, rainfall is expected to decrease by 30% by the end of the century. Emblematic species like rosemary, rockrose and thyme are adapted to dry conditions, but climate change will make them more vulnerable.

Wild bees and stressed rosemary

Our aim is to assess the impact of climate change on pollination, with a team of researchers from the Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE). In the shrubland of the Massif de l'Étoile, around Marseille, we measured the scent emitted by rosemary under present conditions and in dryer conditions (30% less rainfall). To do this, we enclosed flowering rosemary branches in small bags constantly flushed with ambient air, and we trapped the fragrance molecules in a small tube inserted into the outlet of the bag. The contents of the tube were then analysed in the laboratory. Rosemary under stress was found to emit a more intense and diverse scent (with more molecules). Although the human nose may not be able to detect the difference, bees have a much finer sense of smell. We measured how bees responded to the change in floral scent, that is to say which plants (stressed or not) did they preferably visit. We finally looked at the impact of their choices on fruit production.

 <img alt="" src="https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=582&fit=crop&dpr=1 600w, https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=582&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=582&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=731&fit=crop&dpr=1 754w, https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=731&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/278678/original/file-20190610-52771-lp5ndf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=731&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A wild bee collects nectar from a rosemary flower. Coline Jaworski, CC BY-NC-ND

Domestic bees abound in the Massif de l'Étoile and they dominate the community of pollinators. They are larger than wild bees, and they collect nectar in small groups. Probably as a result of these differences, we noticed an allocation of resources: domestic bees showed a preference for non-stressed plants (perhaps because of the superior quality of their resources), whereas small wild bees were more likely to choose stressed plants. Apart from changes in floral scent, we were not able to demonstrate any differences in terms of the quantity of flowers, colour or nectar production. However, the nectar might have been affected, for example in the production of different sugar blends.

Finally, we observed that the stressed plants produced slightly more fruit (and therefore more seeds), which suggests a greater pollination efficiency of small wild bees. By choosing the stressed plants and in the context of our study, wild bees therefore boost the production of plants that are better suited to dry conditions, which could enable the plant community to better react to climate change.

To protect wild bees and to safeguard their function of pollination, both in natural and in agricultural environments, it is important to accurately measure how climate change affects the production of floral resources in each environment. Competition with domestic bees could also be mitigated by ensuring a balance between the density of resources and the density of hives: if the environment cannot produce enough flowers to sustain beehives, wild bees will be the first to lack resources.

 <img alt="" src="https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=121&fit=crop&dpr=1 600w, https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=121&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=121&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=152&fit=crop&dpr=1 754w, https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=152&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/202296/original/file-20180117-53314-hzk3rx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=152&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">

Created in 2007 to help accelerate and share scientific knowledge on key societal issues, the AXA Research Fund has been supporting nearly 600 projects around the world conducted by researchers from 54 countries. To learn more, visit the site of the AXA Research Fund.

Translated from the French by Jemma Dunnill for Fast ForWord.

Coline Jaworski receives funding from AXA Research Fund. Coline is currently affiliated to (1) Aix-Marseille University, IMBE; (2) Oxford University, Department of Zoology.

Benoît Geslin is currently affiliated to Aix-Marseille University, IMBE

Catherine Fernandez does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
 As climatic conditions change, plants' odours are altered, with direct consequences for pollination, especially by bees. Coline Jaworski, Chercheuse Postdoctorale en écologie évolutive / Postdoctoral Fellow in evolutionary ecology, Aix-Marseille Université (AMU) Benoît Geslin, Maître de conférences en écologie, Institut méditerranéen de biodiversité et d'écologie marine et continentale, Aix-Marseille Université (AMU) Catherine Fernandez, Professeur Ecologie chimique, Aix-Marseille Université (AMU) Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/109189 2019-03-15T05:34:20Z 2019-03-15T05:34:20Z Guinea flowers are fierce and golden

This guinea flower is called 'fierce' after its sharp, painful needles.  The Conversation/Shutterstock

Welcome to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian. Read more about the series here or get in touch to pitch a plant at firstname.lastname@example.com.

I first became interested in guinea flowers when I heard of a plant growing in Queensland's White Mountains nicknamed "excruciating" by all who handled it, because of the pungent needle-like leaves which attached themselves to fingers and clothes.

This species is a guinea flower, now scientifically named Hibbertia ferox, meaning "fierce". Guinea flowers grow across Australia, from the rainforest to semi-arid areas.

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Guinea flowers belong to the genus Hibbertia, which dates back to Gondwana. Members of the genus are easy to recognise, but individual species are hard to tell apart. Their brilliant yellow (or sometimes orange) flowers have petals with a notch at the apex, and they were thought to resemble the appearance of the 18th-century coin known as a golden guinea. As usual there are a couple of exceptions – at least two species have petals that lack a notch.

All too often these small shrubs and woody climbers grow in areas likely to be razed for urban sprawl or mining.

 <img alt="" src="https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=802&fit=crop&dpr=1 600w, https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=802&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=802&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1008&fit=crop&dpr=1 754w, https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1008&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/264059/original/file-20190315-28487-1w13881.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1008&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
  The Conversation

What we know about Hibbertia

English merchant and amateur botanist Henry Charles Andrews named the genus Hibbertia after his friend George Hibbert (1757-1837). Andrews was an artist and engraver as well as a botanist, and the first species he named was based on a plant collected around Port Jackson.

Around 200 species are recognised but there are many unnamed varieties, particularly in tropical areas. Probably the most widespread species and one of the few cultivated is the climbing guinea flower (Hibbertia scandens). It can be grown readily from cuttings but germinates slowly from seeds.

Most species have hairs covering the leaves, which can be critical for identifying a species. Under a good hand lens or a simple microscope their variety and beauty is obvious. In some species the hairs are straight. In others they are branched with arms resembling the spokes on a star, the so-called "stellate hairs".

Some species have scales – flat, plate-like structures – on their leaves and flowers. Sometimes there are large and small scales on the one surface.

The leaves are also diverse in shape and form: some leaves are shaped like spear and thick, as in Hibbertia banksii of the eastern Cape York area, others are needle-like with margins rolled towards the lower midrib, with a sharp, blood-drawing tip, as in Hibbertia ferox.

 <img alt="" src="https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=276&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=276&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=276&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=347&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=347&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263831/original/file-20190314-28487-8gdca6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=347&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A 1795 guinea coin from the reign of George III. Wikipedia

The flowers are usually solitary and roughly 2cm in diameter, but in some of the northern species they grow in spikes roughly 4-5cm across.

Five sepals surround the five petals, which are broadest towards the top. The flowers usually close at night and reopen the next day.

A distinctive feature is the arrangement of the stamens (the male parts). These may be all on one side of the carpels (the structures containing the unfertilised seeds at the centre of the flower) or may form a form a ball in the centre. The number varies between species from fewer than 10 to more than 100.

 <img alt="" src="https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263546/original/file-20190313-86703-1b0ca79.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Hibbertia ferox was nicknamed 'excruciating' because of its needle-like leaves. Shutterstock

Floral frolics

For a plant to be involved in sex of a floral kind it needs to offer rewards for services rendered. Sometimes guinea flowers grow sterile stems, which add to the floral display and provide a food source, particularly for beetles. They are messy eaters, chewing on various plant tissues as they wander around the flower's surface, but they do help to transfer pollen to the stigmas, or female parts (and no doubt are involved in sex with their own kind).

Guinea flowers don't produce nectar to tempt pollinators, but people have reported them producing weak fragrance. There's some dispute over how pleasant the smell is, with some describing it as sweet and others insisting it smells like cow dung. There have been only a couple of reports of what this smell resembles, so we need you to go and stick your nose in a freshly open flower. (Make sure to check – is the fragrance there all day or only in the morning?)

However, there is plenty of pollen. If you look closely at the anthers, those yellow sacs on the top of a thin stalk, you will see either an opening or pore at the top, or a slit down the side through which pollen can escape. Whether the marauding bug causes the pollen to spray out through the top or it accidentally falls on the bug through the slit, the bug gets dusted in pollen and then this can get brushed off on the female parts or stigma. Bees and flies are the most common bugs seen around guinea flowers.

The fruit is composed of 2-5 loosely adhering capsule-like follicles, surrounded by the five sepals, which remain and do not fall off.

 <img alt="" src="https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=514&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=514&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263549/original/file-20190313-86682-2wbf2t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=514&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Hibbertia scandens, a climbing guinea flower, is commonly known as snake vine. Shutterstock

The fruit contains one or two seeds that are covered by a reddish coating or aril. This nutritious tissue is a valuable food source for dispersers such as ants and birds; birds have been recording spreading the seeds of Hibbertia scandens. However, in the drier areas where these plants are commonly found, ants appear to be the common dispersers.

So next time you are in the bush don't just ignore that small shrubby plant with yellow flowers and notched petals. Stop and admire their beauty.

   À lire aussi : Sustainable shopping: your guilt-free guide to flowers this Valentine's Day

Note if there are any bugs visiting and what they might be doing. Why not record their presence on iNaturalist – an app that lets us record and share your nature encounters – particularly if you are off the beaten track?

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Betsy Jackes ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 The guinea flower grows right across Australia. Betsy Jackes, Adjunct professor, James Cook University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/111557 2019-02-12T13:38:40Z 2019-02-12T13:38:40Z Valentine's Day: five ways to ensure your flowers are ethical

  Anett / shutterstock

If you take an interest in ethical consumerism and plan to treat someone special this February 14, what dilemmas lie ahead? You might already be conscious of getting child labour and slave-free chocolate, a recycled card, even fair trade gold, and perhaps vintage or conflict-free diamonds if it's a very special year. But what about your flowers?

This year one of us (Jill Timms) will spend her Valentine's Day looking at sustainable supply chains in Lake Naivasha, Kenya, where hundreds of flower workers will be recovering from their busiest time of year.

Across the world, 250m rose stems will be produced for the day. Of those exported to the EU, 38% are from Kenya, where flower export values have trebled this decade. Governments in Ethiopia, Tanzania and more recently Uganda and Rwanda, are also pursuing expansion, with flowers now accounting for 10% of East African exports.

That part of the world has a natural abundance of heat and space, and lots of available cheap labour. Flowers could help the regional economy to "bloom". However, there are significant social and environmental challenges, such as the massive population growth around Lake Naivasha which contributes to pollution and has helped cut the lake's volume in half.

Our own research project on sustainable flowers focuses on stakeholders from different parts of the supply chain. But you definitely have a role to play here too, and it begins with asking questions of the flowers you buy. Here are our top five:

1. Where are the flowers from?

Geography matters. Some flowers travel by sea, some cargo plane and others in the hold of passenger jets, all with very different carbon footprints. For instance more than 90% of UK flowers are imported, mostly from the Netherlands, although Kenya and Columbia are increasingly important suppliers. Chemical sprays freeze flowers to extend life, and they often travel via the Dutch flower hub. Historically the Netherlands has been the industry powerhouse, but now works hard to retain this in the face of direct supermarket buying, growth in Chinese, East African and South American production, and criticism of the extra "flower miles" involved in transporting via Holland.

So provenance is important, but you may struggle to know this. Flowers are not always labelled, labels don't always specify origin or may list the Netherlands if bought at auction, and bouquets include flowers from multiple sources. Even when the origin is known, things can still be unclear as sustainability issues vary widely by country and flower.

Of course, very short supply chains are possible for some varieties (the shortest being from your garden, if you have one). But this sort of localised growing does not satisfy the demand for volume, variety and year-round supply, or indeed guarantee sustainability in terms of energy, pesticide use and so on.

2. Have the flowers met any standard of practice?

In response to ethical concerns, "certification" schemes are becoming more common. Yet we find consumers, florists and even wholesalers are often unaware or misunderstand these, with Fairtrade still being the only one with wider recognition.

We are working with bodies including the British Florist Association to educate florists about standards, and wholesalers like Fleurmetz to review how certification can be more visible. You can help by asking your florist if their flowers are certified. If they don't know, ask to see delivery boxes.

3. Who does your purchase support?

In the UK, about 60% of flowers are bought from supermarkets, with the rest mostly from florists. Supermarkets have their pros and cons. Flowers tend to be better labelled, and they are more likely to cut out the auctions and buy direct from growers, which assures provenance and means they can influence standards. However the supermarkets might not share this information, and their demands on price, volume and the short time from field to market can put inordinate pressure on farms.

In contrast, the demise of the high street, Brexit uncertainty and increased online and supermarket competition, has led to "support your local florist" campaigns. Interestingly, some florists have responded by using sustainability as a selling point.

Certifications can help you support farms that claim good practice, but could your purchase also promote development – a familiar argument for global trade? Of course it depends how it is done. For example, the Ethiopian government attracted lots of foreign investment in flower farming. However, incentives included controversial land use agreements that led to civil unrest in 2016, with several foreign-owned flower farms badly damaged or burnt to the ground.

4. What are your own priorities?

There is always a trade-off. Flowers grown in greenhouses in Holland use enormous amounts of energy, but travel less. Lake Naivasha roses enjoy natural heat and light, but are flown many miles and can be chemically treated to survive. So your priorities need to guide your purchase: environmental issues include carbon footprint, chemical use, ecological degradation and water use; social issues include health and safety standards, gender discrimination, precarious employment and land rights.

Accordingly you might choose locally-grown seasonal or organic  flowers, or seek growers who support community development or rights for women workers.

5. What will you do with your flowers?

Eco-florists such as Wild and Wondrous are raising awareness of alternative practices. Take in your own vase to avoid cellophane packaging or ask for reusable and recycled options like StemGem. When presenting your blooms, take inspiration from the #nofloralfoam campaign. Treat your flowers well by refreshing water and trimming, keep them out of heat and sunlight, then recycle as green waste to make their journey worthwhile.

St Valentine's is a day to express our love, so demonstrate yours for people and planet. The supply chains are complex, but our simple advice is to ask questions.

Jill Timms receives funding from the British Academy/Leverhulme Trust.

David Bek receives funding from WWF SA's Table Mountain Fund.
 Many roses are grown in energy-intensive greenhouses, shipped long distances or treated with chemicals. Here's what to ask your florist or supermarket. Jill Timms, Senior Lecturer in Strategic Management, Coventry University David Bek, Reader in Sustainable Economies, Coventry University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/108271 2019-01-15T12:55:36Z 2019-01-15T12:55:36Z How harvesting natural products can help rural people beat poverty

Ornamental craft made from palm leaves and pine cone in grass baskets are sold in Eswatini.  Deepa Pullanikkatil

Every day, people around the world harvest natural products like fungi, plants, bark, flowers, honey and nuts. These non-timber forest products, as they are known, can play an important role – particularly for people living in rural areas.

Products like honey and nuts can be sold. Plants and plant fibre can be used to create furniture, cloth and crafts; herbs processed to make herbal remedies and leaves and flowers sold for ornamental uses. All this contributes to income generation and is a valuable resource for alleviating poverty in rural communities.

Yet Non-Timber Forest Products (or NTFPs) don't often feature in discussions about poverty reduction and alleviation. One of the reasons for this is probably the lack of qualitative studies on the topic; the kind which feature stories from people who have used them to escape poverty. Users' voices haven't been heard enough to help scholars and policymakers understand the links between these products and poverty alleviation, and to harness these in poverty reduction strategies.

In our new book published by Springer, Poverty Reduction Through Non-Timber Forest Products, we have tried to fill this gap. Interviewees from Mexico, Guatemala, Nicaragua, Peru, Brazil, Portugal, Italy, Nepal, India, China, Uganda, Swaziland, Malawi, Cameroon, Mozambique and elsewhere shared their stories of using various products to create small enterprises and earn money.

Many have also been able to survive shocks such as crop failure, illness, retrenchment and the loss or estrangement of a family's sole breadwinner. This shows how non-timber forest products can act as "safety nets".

Non-Timber Forest Products are dwindling worldwide; climate change and overuse of land are contributing to this trend. But such products are still common in many parts of the world and – while there is no one-size-fits-all solution for poverty alleviation – they should be studied and considered in governments' poverty reduction plans.

Our findings suggest that trade in these products should be promoted among poor people. Governments and development partners need to offer the necessary training, support and access to markets and finance to ensure this happens.

Stories from Africa

There are many ways in which Non-Timber Forest Products can be used as an income source. Several approaches are examined and profiled in our book.

In Uganda, for instance, we focused on a small-scale women's industry called Easy Afric Design which uses bark cloth made from the fig tree to create handbags and folders.

The women had to overcome the stigma of using bark cloth as a raw material, as it has historically been used for burials. To show other women that the material could be used for more than its traditional purpose, founder Sarah Nakisanze wrapped the bark cloth around her as a skirt.

Now, several rural women work for the company from their homes, making products from bark cloth. This empowers women who didn't have any other source of income. Many have been able to save money to send their children to secondary school and to purchase assets.

In Swaziland, we profiled Paul Dlamini. He harvests medicinal plants from indigenous forests and sells them in his herbalist shops around the country. With this income he set up a five roomed house, educated nine children and employed several people. He has been able to educate his children beyond his own level of schooling, and to improve his family's livelihood.

We also share stories from Cameroon and Malawi of people who produce honey and have used the income from their sales to lift themselves out of poverty. The farmer who launched the Malawian initiative, Arnold Kasumbu has become so successful that he now trains other farmers, as well as university students.

Raul Sebastião Nhancume, from Mozambique, had to drop out of school due to poverty and later learnt to use palm (Hyphaene coriacea) leaves to make furniture for a living. Now he has two employees in his furniture manufacturing workshop and sells his products in Mozambique and South Africa. With the income from furniture making, he was able to buy school supplies and uniforms for his two children and has also built a two bedroom brick home.

By investing their earnings into children's education, many of the people we interviewed were looking to ease inter-generational poverty and improve younger generations' opportunities.

Successful approaches

Some countries have made inroads in using their Non-Timber Forest Products trade for poverty alleviation. As we outline in the book, Brazil and India have provided training, marketing support and certification for NGOs using these products. Other countries could learn from these approaches.

A deeper understanding of how Non-Timber Forest Products can become income sources, as provided through people's own stories, helps to inform poverty reduction strategies in ways that broad statistics and data can't.

Deepa Pullanikkatil does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
 Non-Timber Forest Products don't often feature in discussions about poverty reduction and alleviation. Deepa Pullanikkatil, Co-Director Sustainable Futures in Africa (SFA) Network (Funded by Scottish Funding Council and allocated to the University of Glasgow), Consultant based at CANGO in Eswatini and Co-Founder -Abundance, University of Glasgow Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/105218 2018-10-20T12:18:40Z 2018-10-20T12:18:40Z Australia's native rhododendrons hide in the high mountain forests

Rhododendron lochiae, photographed on Bell Peak. Image by Dan McLeod

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The 1800s was a time of colonial expansion across the globe. During this time the great and the good of Britain filled their grand gardens with exotic novelties from all corners of the world.

Amongst these were many species of Asian rhododendron, a diverse and colourful genus of shrubs and small trees, whose high altitude origins made them well suited to the cool temperate climate of England and Scotland.

   À lire aussi : The road to here: rivers were the highways of Australia's colonial history

Throughout the 19th century, commercial collectors and field naturalists discovered rhododendron species in southern China, the Himalayas, on the high peaks of Borneo, Java and especially New Guinea.

These finds lead Victoria's government botanist of the time, Ferdinand von Mueller, to speculate about finding rhododendrons on the high tropical mountains on the northeast coast of Queensland. He wrote:

When in 1855 [I] saw… the bold outlines of Mount Bellenden-Ker, the highest mount of tropical Australia, towering to 5,000 feet, [I] was led to think, that the upper region might prove to be the home of species of Rhododendron… forms of plants characteristic of cool Malayan sylvan regions.

But the lofty heights of Mt Bellenden Ker were unknown to European Australians. It would be another 32 years before an expedition led by naturalist W.A. Sayer reached its central peak.

 <img alt="" src="https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=802&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=802&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=802&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1008&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1008&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241363/original/file-20181019-67167-136n0xn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1008&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
  The Conversation, CC BY-ND

Sayer's expedition, accompanied by two indigenous assistants, reached the mountain's high ridge after several mishap-filled attempts. It was here they confirmed Mueller's suspicions. Sayer's account of its discovery is interesting:

The top of the range is razor-backed, and on travelling along the range beyond the spur by which we ascended, I could not see the sides, they being, if anything, hanging over. We tumbled rocks over, but could not hear them fall.

It was here that I observed the Rhodendron Lochae growing, and asked the Kanaka to get it; but he remarked, 'S'pose I fall, I no see daylight any more; I go bung altogether;' so I had to get it myself.

Mueller received the hard-won specimens and named the species Rhododendron lochae (later corrected to R. lochiae) after Lady Loch, the wife of the Victorian Governor.

Since then, rhododendron plants have been found on nine peaks and tablelands in the Wet Tropics region of north Queensland. Populations on peaks south of Cairns are called Rhododendron lochiae, whilst plants growing on mountains to the north of Cairns are considered by some to be a distinct species: Rhododendron viriosum.

 <img alt="" src="https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241500/original/file-20181020-105757-zudit6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Australian rhododendron at Smith College Botanical Garden. Ren Glover/Flickr, CC BY-NC

Both northern and southern plants are straggly shrubs that grow in thin soils or rock cracks, sometimes in open cloud-swept boulder fields, sometimes in deep shade along creeks, or rarely as epiphytes on moss-covered trees. They produce bunches of gloriously red, bell-shaped flowers, followed by dry brown capsules filled with small winged seeds that are apparently spread by wind.

They grow slowly but with relative ease from cuttings, and are often cultivated in gardens and nurseries in temperate Australia. However, over time knowledge of the precise origin of these cultivated plants has been lost, which means they are unsuitable for detailed scientific investigations.

All of Australia's rhododendron populations are located at altitudes above 950m in National Parks within the Wet Tropics World Heritage Area. Most are difficult to access, requiring arduous climbs on rough foot tracks through leech-infested rainforest. And yet, although isolated in protected areas, they are threatened by human activities: loss of habitat due to climate change.

Recent climate modelling research published by scientists from James Cook University and the CSIRO predicts significant reductions in suitable habitat for a suite of mountaintop flora species in Australia's tropics (our rhododendrons were not included in the analysis, but occupy the habitats assessed).

The habitat of many of these species is predicted to disappear altogether well before the end of the century.

 <img alt="" src="https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/241499/original/file-20181020-105776-13a60x9.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Conservationists are racing to preserve samples of native rhododendrons. Author provided

Using rhododendron as a model, the Australian Tropical Herbarium at James Cook University is working to save these threatened species through "ex situ" conservation – cultivation in temperate zone public gardens, well outside their natural range. Because the threatening process – climate change – is not readily mitigated, establishing precautionary ex situ collections is the only viable conservation intervention for these plants.

With funding from the Australian Rhododendron Society Victoria Branch and the Ian Potter Foundation, and the support of traditional owners, Queensland National Parks and the Wet Tropics Management Authority, we have mounted expeditions to collect samples from most of the known populations.

These expeditions have put expert naturalists into rarely visited and challenging environments. Beyond gathering rhododendron samples, new moss species have been discovered and are being named, a fern previously thought extinct was rediscovered, and beautiful little epiphytic orchids have been found on a mountain where they'd not previously been recorded. Golden bower-bird bowers have been mapped in remote mountain rainforests, and a likely new species of snail has been discovered.

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Australia now has a well-documented and genetically diverse collection of native rhododendron plants thriving in the Dandenong Ranges Botanic Garden.

We plan to expand this work, ensuring the preservation and public display of rhododendron and many other mountain species threatened by climate change.

 <img alt="" src="https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=199&fit=crop&dpr=1 600w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=199&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=199&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">

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Stuart Worboys receives funding for this research from the Australian Rhododendron Society and the Ian Potter Foundation. He sits on the Management Committee of the Environmental Defenders Office of North Queensland.
 European settlers suspected Australia's high tropical forests hid native rhododendrons. Stuart Worboys, Laboratory and Technical Support Officer, Australian Tropical Herbarium, James Cook University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/103224 2018-10-12T04:32:11Z 2018-10-12T04:32:11Z Leek orchids are beautiful, endangered and we have no idea how to grow them

  Marc Freestone/The Conversation

Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.

Leek orchids don't have many friends. Maybe it's because they lack the drop-dead gorgeous looks of many of their fellow family members. Or perhaps it's because they're always the first to leave the party: as soon as sheep or weeds encroach on their territory, they're out of there. Whatever the reason, you don't see leek orchids around very often.

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Leek orchids are small, ground-dwelling native Australian orchids, so called for their single spring-onion-like leaf, which shoots up from an underground tuber each autumn. In the spring, if there's been enough rain, they produce a spike of small brown, green or white flowers.

Like many native orchids, they are battling extinction. My research involves trying to find the secret to propagating them – something we still don't fully understand.

 <img alt="" src="https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=802&fit=crop&dpr=1 600w, https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=802&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=802&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1008&fit=crop&dpr=1 754w, https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1008&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/240377/original/file-20181012-119138-fqdcnb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1008&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
  Marc Freestone/The Conversation

Extinction

Australia is quite rich in orchids with more than 1,300 native species (by contrast, there are only about 200 species in all of North America). About 140 of these are leek orchids, and most live in bushland remnants across the south of Australia.

With a preference for fertile soils and relatively high rainfall, these little plants suffered severely during the period of agricultural expansion in the southeast of the country during the first half of last century. Rabbits, weeds, inappropriate fire regimes, and declining rainfall patterns continue to plague those that survive, which often hang on in narrow roadsides, beside rail lines or in rural cemeteries – tiny pockets of land that were never ploughed.

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Almost one-third of all leek orchid species are at risk of extinction. Some are already extinct, such as the Lilac Leek-orchid (Prasophyllum colemaniae). It once grew in Melbourne's outer eastern suburbs, but disappeared when an upgrade of a rail line in the 1970s destroyed the last population. Standing half a metre tall, with fragrant purple-white flowers, it was said to be the most beautiful of all leek orchids.

 <img alt="" src="https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/240379/original/file-20181012-119114-1p6txa7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Collecting seed in the Alpine region. Marc Freestone

Native orchids are rebounding – but not leek orchids

Fast forward to 2018 and things have changed. The Royal Botanic Gardens Victoria now hosts the largest orchid conservation program in the world. Dozens of critically endangered native orchids from the southeast mainland are being brought back from the brink of extinction through propagation and reintroduction programs.

But not leek orchids.

That's because we still don't know how to grow leek orchids successfully. In fact, growing any type of orchid is hard work. For a start, orchid seed is microscopic. It is so small it doesn't contain any food for the germinating orchid seedling.

Instead, all orchids rely on symbiotic fungi that live in their roots and the surrounding soil and are required to inoculate the orchid seed – the fungus literally pumps food into the seeds to get them to germinate. We have no idea why these fungi do this, but we can replicate this scenario in the lab by carefully extracting fungi from the roots of a wild orchid plant, growing the fungi in a petri dish, and sprinkling in the orchid seed. But for some reason, leek orchid seed rarely germinates, and if it does, the young seedlings usually brown off and die.

 <img alt="" src="https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/240364/original/file-20181012-154583-1rucaqs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Three month old baby leek orchid seedlings. Of the few seeds that germinate, most won't survive past this point. Marc Freestone

How to grow leek orchids is the subject of my PhD project with the Australian National University, based at the Royal Botanic Gardens Victoria. We have many theories about what might be going on and we're looking at seed viability, growing conditions, and the relationship between leek orchids and their symbiotic fungi.

It's a race against time to work out how to grow them before more species – like the Shelford Leek-orchid (Prasophyllum fosteri) from western Victoria, which is now down to only a handful of wild plants – go extinct.

Why should we care?

At first glance, leek orchids do not appear to be particularly useful for anything. They can't cure cancer or be traded for Bitcoin. So who cares if they go extinct?

 <img alt="" src="https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=799&fit=crop&dpr=1 600w, https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=799&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=799&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1004&fit=crop&dpr=1 754w, https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1004&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/240365/original/file-20181012-119126-v7n9ak.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1004&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 There are only a few hundred coast leek orchids remaining. Marc Freestone

Well, the first point is we don't know enough about leek orchids to be able to conclude that they are indeed completely useless to the human race. Second, leek orchids probably used to play an important ecosystem role in the lowland grasslands of southeastern Australia.

Up in the Australian Alps there are several species of leek orchid that are still very common, their flowers providing an important food source for insects. Seeing the massed flowering of the Alpine Leek-orchid (Prasophyllum tadgellianum) in summer really gives you a feel for what the lowland grasslands would have been like once upon a time, when species like the Gaping Leek-orchid (Prasophyllum correctum) would have numbered in the millions. Now there are perhaps 10 plants left.

If it goes extinct, Australia will have lost part of what makes it unique. A small part, perhaps, but when added to all the other threatened species in this country, a significant part.

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Personally, I find leek orchids delicate and utterly defenceless against humans, who have engulfed their world. Ironically, some species are now totally dependent on us for their survival. I feel a great sense of responsibility to help them.

 <img alt="" src="https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=199&fit=crop&dpr=1 600w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=199&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=199&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/238283/original/file-20180927-48650-1veiqyi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">

Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.

Marc Freestone receives funding from Hermon Slade Foundation, Australian Government National Environmental Science Programme – Threatened Species Recovery Hub, Victorian Government.
 Scientists are racing against the clock to figure out how to propagate the rare leek orchid before it goes extinct. Marc Freestone, PhD Candidate, Australian National University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/99418 2018-08-14T13:59:49Z 2018-08-14T13:59:49Z Making sunlight liquid – a brief history of sunflowers

  Salajean/Shutterstock.com

Fields of sunflowers are now a common – and beautiful – sight all over the world. They have inspired artists from Van Gogh to Klimt, and continue to do so in the age of Instagram, if the recent selfie craze is anything to go by and as one Canadian sunflower farm discovered. It was forced to shut after thousands of tourists seeking the perfect selfie caused chaos. An astonishing 7,000 vehicles caused a traffic jam stretching over four kilometers.

But when sunflowers were introduced to Europe from the Americas in the early 16th century they were little more than garden novelties. The 16th-century English herbalist, John Gerard, was disappointed that the sunflowers in his Holborn garden in London were only 4.3 metres tall (those of his European competitors reached 7.3 metres). Today, sunflowers, with their massive, yellow flower heads are among the most recognisable plants on the planet.

 <img alt="" src="https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=757&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=757&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=757&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=951&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=951&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231733/original/file-20180813-2894-ocj0a9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=951&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Van Gogh's sunflowers. Wikimedia Commons

The growth in their prevalence – and that of sunflower selfie snaps – is largely due to their ballooning use for oil. Over the last 60 years, changes to our diets and industrial needs mean the area of global oil crop production has more than doubled. Four oil crops consume most of this land: oil palm, soya, rape and sunflower.

Sunflowers have two main commercial uses, oil and confectionery (for direct seed consumption). Oil varieties of the flower have small, black, oil-rich seeds with thin hulls, which are pressed to produce an edible, almost tasteless, pale oil, rich in unsaturated fatty acids (especially oleic acid and linoleic acid). The oil is popular for cooking, margarine manufacture and even bio-diesel production. Leftovers from oil extraction are used to make high-protein animal feed. Confectionery types, on the other hand, have large, striped, oil-poor seeds with thick hulls. Both oil and confectionery types are the results of centuries of careful selection and breeding from wild plants.

In North America, the sunflower's native continent, the harvest contributes little to global production; peak production happened in the late 1970s only to fall dramatically in the 1980s. Today, most sunflowers are grown in the former Soviet Union.

Soviet sunflowers

The annual sunflower, a member of a genus of about 50 species from the Americas, was domesticated in North America about 5,000 years ago. Native North American uses of sunflower ranged from food and medicine, through a fibre and dye plant to a source of musical instruments and bird snares.

Commercial interest in sunflowers as an oil crop was slow to develop across most of Europe and North America. In contrast, Russians were using sunflowers as an oil crop by the late 18th century, perhaps because the Russian Orthodox Church did not prohibit the oil's use during Lent. By the end of the 19th century, Russians had selected highly productive oil and confectionery varieties, which were re-imported to North America in the baggage of Russian immigrants.

During the early 20th century, the Soviet plant breeder Vasilii Stephanovich Pustovoit began selecting sunflowers for oil content. In 1913 seeds contained approximately 30% oil, by the late 1950s seeds contained approximately 50% oil. Much of the change was achieved by breeding for thin hulls surrounding the kernels. By the 1960s, Western commercial sunflower oil production was based on the Soviet sunflower variety "Peredovik".

   À lire aussi : The flower breeders who sold X-ray lilies and atomic marigolds

Soviet sunflower seeds even got mixed up with the Cold War – high-quality seeds surreptitiously moved among Soviet and American plant breeders.

Soviet sunflower breeders used naturally occurring variation within the annual sunflower to make commercial progress. But by the mid 20th century, North American breeders were taking a different approach, crossing wild and cultivated sunflower species to exploit the yield advantages associated with hybrid vigour. Today, most commercial sunflower farmers grow hybrid sunflower seed.

Hybrid varieties

Hybrid sunflower seed can be made by slowly, meticulously and expensively emasculating individual flowers to create females, which are then pollinated by hand. Alternatively, mutant sunflowers, incapable of producing fertile pollen, are used as female parents in hybrid crosses.

 <img alt="" src="https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=820&fit=crop&dpr=1 600w, https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=820&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=820&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1030&fit=crop&dpr=1 754w, https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1030&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/231734/original/file-20180813-2924-lx2lw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1030&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Helianthus annuus, 1882. Wikimedia Commons

Insects are essential for producing the vast quantities of the hybrid sunflower seed planted each year, since pollen must be transferred from male-fertile to male-sterile plants. Without insects, hybrid sunflower seed production would be uneconomic. But once in the farmer's field, the sunflower crop does not rely on insects: crop seeds are produced by flowers that are fertilised with their own pollen. But new seeds will have to be purchased for the next season.

Sunflower breeding continues in earnest today. New demands are placed on breeders by the environments in which farmers want to grow sunflowers and by consumers in the ways they want to use the harvest. Height, for example, is something every child wants their sunflower to achieve. But to the farmer, tall sunflowers must be avoided. Energy used to push up stems cannot be used to make seeds. And heavy rains and strong winds will knock over tall, top-heavy plants.

The dramatic changes of form and use of sunflowers over the last century show what can be achieved by breeders if suitable genetic resources are available. If we continue to adapt sunflowers to our needs as climates change, we must ensure diverse genes are conserved for future generations – ensuring those sunflower fields remain on offer as the perfect place to take a picture.

   À lire aussi : After Svalbard: why safety of world seed vaults is crucial to future food security

Stephen Harris ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 Fields of sunflowers are now a common sight all over the world – but this has only been the case relatively recently. Stephen Harris, Associate Professor in Plant Sciences, University of Oxford Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/94784 2018-04-16T09:00:24Z 2018-04-16T09:00:24Z Chamomile tea may help control diabetes – as my research into 19th century dyes revealed

  ConstantinosZ/Shutterstock.com

Chamomile – that yellow flower so often made into a tea, enjoyed before bed – is a very interesting plant. It was recently discovered that the humble flower may control or even prevent diabetes – and now my research into historical textile dyes has helped to identify the specific compounds involved. That bedtime herbal tea may be doing many people a lot of good.

I've been working with Chris Rayner for over 15 years to develop new techniques to identify the chemistry of natural colourants used throughout history to dye textiles. Before William Perkin's serendipitous 1856 discovery of mauveine, the first synthetic dye, textile fibres were dyed with coloured extracts of plants and animals.

Nature makes a complex cocktail of different compounds in these dye plants, and many of these are transferred to textiles during dyeing. We analyse historical artefacts to see if these compounds are present to try to determine when, where and how they were dyed and with what plant. The chemistry and ratio of these molecules can provide significant information about which plant species was used to dye the fibres or the technique used for the dye process. In the context of historical textiles, this information is of paramount importance for conservation and restoration purposes, as well as the generation of information on the ethnographic origins of the artefacts.

 <img alt="" src="https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=653&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=653&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=653&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=821&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=821&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214741/original/file-20180413-127631-1hmy9iu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=821&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Dyeing wool cloth, 1482. British Library Royal MS 15.E.iii, folio 269

So what does this have to do with diabetes? Well, many of the techniques that have been used to extract the dyes from textile samples cause damage to the dye molecule, resulting in a loss of information about the chemical fingerprint potentially available to conservators. But we have developed new "soft" extraction methods using glucose, which can preserve the dye molecule during extraction and analysis, and have used these new techniques to investigate dyes that were commonly used prior to the mid-19th century.

One such plant used throughout history was chamomile, which gives a bright yellow colour on wool, cotton and other natural fibres. There is evidence of its use in Europe and Asia to dye textiles dating back many hundreds of years. We identified the colourants and other natural components present in several species of chamomile in our attempts to understand their coloration properties and their identification in historical textiles, in the process significantly developing our knowledge of their complex chemistry.

This would have been interesting from a pure conservation and dye chemistry perspective. But then members of our team had a chat with another research group, led by Professor Gary Williamson in the School of Food Science and Nutrition, and it became apparent that we had a mutual interest in the chemistry of chamomile.

As a food, most people will be familiar with chamomile's use as a herbal tea, often associated with aiding sleep. Indeed recognition of its medicinal properties as a relaxant and sedative is exemplified by its listing as an official drug in the pharmacopoeias of 26 countries, including the UK. But we didn't realise that it potentially has other dietary benefits. German chamomile has been taken for digestive problems since at least the first century CE.

 <img alt="" src="https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214739/original/file-20180413-584-enbg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 German chamomile. JSOBHATIS16899/Shutterstock.com

This team has spent the last few years studying the link between dietary components and carbohydrate digestion: specifically, how certain natural compounds can help to control blood glucose levels. They had screened several plant extracts and identified German chamomile (Matricaria chamomilla) as very effective in controlling diabetes in 2017. But what was really important was to understand which compounds in particular were responsible for this activity. We wondered if our research on natural dyes in chamomile could help with this.

We applied the techniques that we had developed for extraction of historical textiles to extraction and analysis of chamomile flowers. Working together, we identified four specific compounds that are active in chamomile and able to control carbohydrate digestion, drawing on our experience of dyestuff analysis.

Two of these compounds, apigenin-7-O-glucoside and apigenin, are yellow colourants that we had previously seen in wool textiles dyed with chamomile. The other two compounds had been previously misidentified by other researchers, but we correctly identified them as (Z) and (E)−2-hydroxy-4-methoxycinnamic acid glucosides. We studied the contribution of these four compounds to the overall bioactivity of chamomile, and found that, taken together, they were able to modulate carbohydrate digestion and absorption. There is also the potential to extract and concentrate these components from chamomile for medicinal application.

 <img alt="" src="https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/214742/original/file-20180413-587-tc0oxx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Chamomile chemical structures. Richard Blackburn, Author provided

So simply put, drinking chamomile tea may be helpful in controlling or even preventing diabetes. And excitingly, it seems that understanding the chemistry of plant dyes in common use prior to the mid-19th century could unlock new treatments for modern day medicine.

Richard Blackburn receives funding from BBSRC, Clothworkers' Foundation, DEFRA, EPSRC, Innovate UK and National Institute for Health Research. He is affiliated with The Society of Dyers and Colourists and The American Chemical Society.
 That pre-sleep herbal tea may be doing many people a lot of good. Richard Blackburn, Associate Professor and Head of The Sustainable Materials Research Group, University of Leeds Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/92673 2018-04-15T20:13:55Z 2018-04-15T20:13:55Z Plants use advertising-like strategies to attract bees with colour and scent

A honeybee (left), a scarab beetle (middle), and a fly (right) feeding on flowers of the white rock rose in a Mediterranean scrubland.  Aphrodite Kantsa., Author provided

Watching plants and pollinators such as bees can teach us a lot about how complex networks work in nature.

There are thousands of species of bees around the world, and they all share a common visual system: their eyes are sensitive to ultraviolet, blue and green wavelengths of the light spectrum.

This ancient colour visual system predates the evolution of flowers, and so flowers from around the world have typically evolved colourful blooms that are easily seen by bees.

For example, flowers as perceived by ultraviolet-sensitive visual systems look completely different than what humans can see.

However, we know that flowers also produce a variety of complex, captivating scents. So in complex natural environments, what signal should best enable a bee to find flowers: colour or scent?

Our latest research uncovered a surprising outcome. It seems that rather that trying to out-compete each other in colour and scent for bee attention, flowers may work together to attract pollinators en masse. It's the sort of approach that also works in the world of advertising.

   À lire aussi : Want a better camera? Just copy bees and their extra light-sensing eyes

Daunting amount of field work

Classic thinking would suggest that flowers of a particular species should have reasonably unique flower signatures. It makes sense that this should promote the capacity of a bee to constantly find the same rewarding species of flower, promoting efficient transfer of pollen.

So a competition view of flower evolution for different flower species with the same colour – for example purple – would suggest that each flowering plant species should benefit from having different scents to enable pollinator constancy and flower fidelity. By the same logic, flowers with the same scents should have different colours so they're easily distinguished.

To know for sure what happens requires a daunting amount of field work. The challenges include measuring flower colours using a spectrophotometer (a very sensitive instrument that detects subtle colour differences) and also capturing live flower scent emissions with special pumps and chemical traps.

 <img alt="" src="https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/212620/original/file-20180329-189813-1yxos63.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A wild bee of the genus Anthophora upon making the decision to visit the flowers of purple viper's bugloss, in a Mediterranean scrubland in Greece. Aphrodite Kantsa.

At the same time, in order to record the actual pollinator "clientele" of the flowers, detailed recordings of visits are required. These data are then built into models for bee perception. Statistical analyses allow us to understand the complex interactions that are present in a real world evolved system.

Not what we thought

And what we found was unexpected. In two new papers, published in Nature Ecology & Evolution and in Nature Communications, we found the opposite to competition happens: flowers have evolved signals that work together to facilitate visits by bees.

So flowers of different, completely unrelated species might "smell like purple", whilst red coloured species share another scent. This is not what is expected at all by competition, so why in a highly evolved classical signal receiver has this happened?

The data suggests that flowers do better by attracting more pollinators to a set of reliable signals, rather than trying to use unique signals to maximise individual species.

By having reliable multimodal signals that act in concert to allow for easy finding of rewarding flowers, even of different species, more pollinators must be facilitated to transfer pollen between flowers of the same species.

   À lire aussi : Which square is bigger? Honeybees see visual illusions like humans do

Lessons for advertising

A lot of research on advertising and marketing is concerned with consumer behaviour: how we make choices. What drives our decision-making when foraging in a complex environment?

While a lot of modern marketing emphasises product differentiation and competition to promote sales, our new research suggests that nature can favour facilitation. It appears that by sharing desirable characteristics, a system can be more efficient.

This facilitation mechanism is sometimes favoured by industry bodies, for example Australian avocados and Australian honey. En masse promotion of the desirable characteristics of similar products can grow supporter base and build sales. Our research suggests evolution has favoured this solution, which may hold important lessons for other complex market based systems.

A successful colour–scent combination targeted at attracting bees can be adopted by several different plant species in the same community, implying that natural ecosystems can function as a "buyers markets".

   À lire aussi : Curious Kids: Do bees ever accidentally sting other bees?

We also know from research that flowers can evolve and change colours to suit the local pollinators. Colours can thus be changed by flowers if instead of bees pollinating flowers, flies, with different colour perception and preferences, dominate the community.

These findings can also prove useful for identifying those colour-scent combinations that are the most influential for the community. This way, the restoration of damaged or disrupted plant-pollinator communities can become better managed to be more efficient in the future.

When next enjoying a walk in a blooming meadow, remember plants' strategies. The colourful flowers and the mesmerising scents you experience may have evolved to cleverly allure the efficient pollinators of the region.

Aphrodite Kantsa is currently a postdoc researcher at ETH Zurich. For this work, she received funding from the European Union and the Greek state (Heraclitus II Program).

Adrian Dyer receives funding from The Australian Research Council.
 Rather than trying to out-compete each other, flowers may work together to attract bees en masse. It's the sort of approach that is effective in the world of advertising too. Aphrodite Kantsa, Postdoctoral Researcher, University of the Aegean Adrian Dyer, Associate Professor, RMIT University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/91387 2018-02-08T18:12:47Z 2018-02-08T18:12:47Z Sustainable shopping: your guilt-free guide to flowers this Valentine's Day
Valentine's Day means saying it with flowers. Last year Australians imported more than 5.22 million rose stems between February 1 and 14, mostly from Kenya. Assuming typical bouquets of 24 roses, that's 217,500 bouquets sold in two weeks.

The problem is that our pursuit of goodwill and affection towards humanity through the giving of cut flowers is hurting the number-one lady in all of our lives: Mother Nature. If those 217,500 bouquets were each wrapped in 75cm of plastic cellophane, that adds up to more than 163km of plastic wrapping used in a two-week period – just for roses, just in Australia.

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But facts about cellophane probably won't win over your sweetheart. So with Valentine's Day just around the corner, let's consider making smarter, more sustainable flower purchases.

Petal power

In Australia alone, there are more than 900 flower farms intensively cultivating 4,470 hectares in order to supply almost 2,000 florists. However, the majority of cut flowers sold in Australia actually originate overseas, with imports from Ecuador alone valued at A$1.9 million in 2015. If you're asking yourself "why are delicate flowers shipped halfway around the world?" this is a great question.

 <img alt="" src="https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205445/original/file-20180208-180826-w5hiex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 For a sustainable take on the floral Valentine, try a banksia bouquet. Emily Orpin/Flickr, CC BY-NC

Countries near the Equator, like Ecuador, benefit from good growing conditions, including 12 hours of daylight all year round. In these regions, the contribution of the flower industry to the economy of small or less developed countries is often significant.

   À lire aussi : The secret of the world's smelliest flower

In eastern Africa, for example, flowers account for more than 10% of total exports, second only to tea.

Lower wages in countries like Ecuador and Kenya also contribute to the economics of flying cut flowers around the world. Unfortunately, this often comes at a cost for local growers and pickers, who experience poor working conditions.

The thorny carbon issue

In the United States, the roughly 100 million roses grown, shipped and purchased on a typical Valentine's Day produce some 9,000 tonnes of carbon dioxide emissions, from field to florist.

But, as with most things in our complex and busy world, the question of a flower's carbon footprint isn't as straightforward as it might seem. The Netherlands is one of the world's biggest exporters of cut flowers, where the majority are grown in heated or refrigerated green houses.

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Maintaining the controlled environmental conditions inside these buildings requires artificial light, heat and cooling, so each rose grown in The Netherlands contributes an average of around 2.91kg of CO₂ to the atmosphere. In contrast, a single rose grown on a farm in Kenya contributes only 0.5kg.

This is largely because Kenyan hot houses do not use artificial heating or lighting, and most farm workers walk or cycle to work. As a result, flowers grown in tropical regions are sometimes considered low-carbon (of course, this doesn't always factor in international transport).

Pesky pesticides

As flowers are not an edible crop, they are typically exempt from regulations on pesticide use. As a result, the cut flower industry is one of the biggest consumers of pesticides worldwide.

In Kenya and other countries, chemicals such as methyl bromide (and others that are banned in countries like the US) are regularly imported in significant quantities by flower growers for pest control.

   À lire aussi : Love's ruin? Victorian Valentines rival our modern age for cynical cruelty

Worryingly, methyl bromide is an ozone-depleting substance. In some cases, run-off of these chemicals from growing fields adjacent to water bodies, such as Kenya's Lake Naivasha, has resulted in the collapse of fish stocks that are crucial to local communities.

So what can you do?

We don't want to be responsible for a downturn in expressions of love (or a corresponding uptick in conflict), and the good news is that there are plenty of eco-friendly ways to show your devotion.

The best option is to grow your own flowers to give as gifts. You can also give a living plant that can grow in your garden for years to come, reminding you of that special person and day. This is a rule in both of our households, and one our husbands are happy to accommodate – our gardens have never looked so good!

 <img alt="" src="https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/205446/original/file-20180208-180844-1nyczte.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Anthurium aren't Australian natives but their pretty heart-shaped flowers make them a perfect living Valentine. Jim, the Photographer/Flickr, CC BY

If growing or giving living plants isn't an option, go for locally grown organic flowers, as this means fewer "flower miles". Native species or hardy breeds like lilies and birds of paradise require fewer resources and survive for longer in transport, meaning there's less wastage.

   À lire aussi : Stop the miners: you can help Australia's birds by planting native gardens

If you decide to buy imported flowers, look for Green Labels like FairTrade and MPS Florimark indicating that suppliers are members of regulatory schemes.

It's also worth asking (or insisting) that your local florist switch from plastic cellophane wrapping to butcher's paper (or similar).

To get you on your way, here are some sustainable flower growers in different corners of the globe:

Australia:

The Little Flower Farm (Melbourne)

Organically certified flowers from Byron Bay, so pure they're actually sold as an edible product

Give a (living) gift that keeps on giving for months or years to come, from companies such as Growing Gifts

Europe & the Americas:

Florverde Sustainable Flowers (based in Colombia) provide social programs for their workers and implement a range of environmental standards, including rainwater collection and air pollution filters. Florverde are a major exporter to Europe, so look for their label in this region

For 15 years, Organic Bouquet (based in Florida) has helped to convert more than 8,000ha of land to organic and sustainable horticulture

Eco-stems Flower Shop (based in Toronto) doesn't just pride themselves in sustainable flower supply, but takes things a whole lot further. All furniture and fixtures are reclaimed/recycled in store, they only use 100% energy efficient lighting, waste water is collected and re-used, delivery vehicles are hybrid, etc. These guys are definitely going the extra mile!

   À lire aussi : Valentine's day roundup: what research teaches us about romance

Les auteurs ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur organisme de recherche.
 Australians import millions of flowers for Valentine's Day. Let's consider some ways to be eco-friendly. Jennifer Lavers, Research Scientist, Institute for Marine and Antarctic Studies, University of Tasmania Fiona Kerslake, Research Fellow in viticulture and fermentation, University of Tasmania Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/88234 2017-12-12T03:30:30Z 2017-12-12T03:30:30Z Here's looking at Rachel Ruysch's Still life with flowers in a glass vase

Detail from Rachel Ruysch, Still life with flowers in a glass vase, 1716, oil on canvas, 48.5 x 39.5 cm, Rijksmuseum, Amsterdam

Linda Nochlin's provocative question "Why have there been no great women artists?", posed in her groundbreaking 1971 essay of the same name, will resonate with visitors to the exhibition Rembrandt and the Dutch golden age: masterpieces from the Rijksmuseum. It presents a survey of 17th-century Dutch art, which includes only two women amongst the 50-or-so artists represented.

One of these artists, Rachel Ruysch, attracted much attention from visitors on the day I attended the exhibition. While few recognised her name, those I spoke with were more than prepared to label her painting, Still life with flowers in a glass vase of 1716, a "great" work of art. Why then have the talents of women artists like Ruysch not been more widely acknowledged?

 <img alt="" src="https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=700&fit=crop&dpr=1 600w, https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=700&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=700&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=879&fit=crop&dpr=1 754w, https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=879&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/198493/original/file-20171211-27698-p0vkvi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=879&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A portrait of Rachel Ruysch by Godfried Schalcken, circa 1706. Wikimedia images

Partially, this is due to a long history of – at best – neglect of women artists. Until recently, women were regularly blocked from pursuing a career in the arts. Consequently, few managed to establish themselves as professional artists. Ruysch was one of the few successful women artists of her age. Born in the The Hague in 1664, she gained international renown as a painter. Such was her reputation that her paintings regularly garnered prices in excess of most of Rembrandt's – the headliner for the Rijksmuseum show.

Knowing Ruysch's reputation in her own lifetime challenges the notion that the neglect of women artists can somehow be located exclusively within the past, when, it may be presumed, people were less enlightened than we are now. We too are to blame. For generations of critics and historians have been unable to effectively establish artists like Ruysch within the key narratives of art history.

This is, in part, due to the fact that women had very different experiences from the majority of (male) artists. For instance, women rarely had access to the human body to make anatomical studies. This made it problematic for women to paint in some genres. Ruysch mostly painted bouquets of flowers – a subject matter that, to us, may seem less capable of providing deep commentary on the human condition than, say, a self portrait by Rembrandt.

Ruysch's flowers are not beautiful distractions from a more serious art culture, however. They connect with deep cultural and philosophical values. A flourishing mercantile culture brought great wealth to the Dutch Republic, and with it, a taste for luxury goods. Tulip mania swept the Republic, with tulip bulbs fetching vast sums. Tulips could, almost unbelievably, sell for the same price as a house.

 <img alt="" src="https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=737&fit=crop&dpr=1 600w, https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=737&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=737&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=926&fit=crop&dpr=1 754w, https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=926&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/196659/original/file-20171128-2025-1oof2rp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=926&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 The full painting: Rachel Ruysch, Still life with flowers in a glass vase, 1716, oil on canvas, 48.5 x 39.5 cm, Rijksmuseum, Amsterdam. AGNSW

Ruysch's family had a particular connection with flowers. Her father, Frederik Ruysch, was a renowned professor of anatomy and botany. Ruysch's careful observation of the characteristics of flowers in her paintings speaks to a wider social investment in them, as well as the intellectual interests of her family, who valued innovations in empirical and scientific thinking.

Ruysch's purpose in painting flowers is made clear through the recognition of a complex series of viewing experiences in Still life with flowers. Individual flower species are carefully rendered, to be easily identifiable.

Complex symbolism

The breathtaking accuracy in the technical aspect of Ruysch's painting is the first thing to attract our attention. A deeper meaning awaits the viewer however. Complex symbolism runs through the work.

For example, the iris, depicted at the apex of her composition, refers to the Christian trinity, as iris petals form in groups of three. In Christian iconography, the trinity is typically depicted at the top of the composition. Ruysch, too, places her iris here. Furthermore, her flowers are often arranged into highly specific groupings to create a developed meaning for the viewer to decode.

This is the case with the white poppies and the Morning Glory at the centre left of the composition, which refer to the Crucifixion and Resurrection. White poppies are associated with sleep and death and Morning Glory (the blue and white flower behind the poppy, emerging from darkness into light) represents the Resurrection, as the flowers are know to open, from a previously dormant state, towards light at daybreak.

Further revelations come when, upon closer inspection, it is observable that the flowers in the painting are infested with insects. Insects, with their short life spans, speak to the fleeting nature of time. Insects also consume or destroy flowers. Their presence here calls into question the viewer's initial delight in encountering the carefully manufactured loveliness of the work.

The appearance of the insects encourages the viewer to participate in the intellectual game that lies at the heart of the painting's symbolism. At first we are attracted by its beauty – flowers shown in an ideal state of bloom – but only in order to recall the vanities of earthy life, fleeting in nature. Looking beyond these superficial interests, we discover deeper values and mores, as embodied in the Christian spiritual tradition.

As such, Ruysch's work is valuable beyond its ornamental beauty. The painting creates an opportunity to look beyond surface meaning and engage in critical reflection.

Visitors to the exhibition certainly seemed to connect with Ruysch's vision. They lingered in front of the work. They moved close to look at its details and stepped back to take in the full composition. From the conversations I had, it seemed there was a consensus that the painting was mesmerising and complex, rather than a simple, decorative depiction of flowers.

Rembrandt and the Dutch golden age masterpieces from the Rijksmuseum is at the Art Gallery of New South Wales until February 18.

Mark De Vitis ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 During her lifetime, the paintings of Dutch artist Rachel Ruysch sold for higher prices than those of Rembrandt. Why, then, have her talents not been more widely acknowledged in the centuries since? Mark De Vitis, Lecturer in Art History , University of Sydney Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/86768 2017-11-10T01:52:29Z 2017-11-10T01:52:29Z Flowers, remembrance and the art of war

Poppies at the Australian War Memorial in Canberra. katatrix/shuttershock.com

Before 1914, flowers in everyday life spelt beauty, femininity and innocence; they were seen as part of women's culture. But during the first world war, that changed. Men gathered posies of flowers on battlefields and dried them in honour of the dead, they turned to wild flowers as motifs for paintings and photographs, and they recognised in blue cornflowers and red poppies the fragility of life.

Historian Paul Fussell referred to the red poppy, Papaver rhoeas, as "an indispensable part of the symbolism" of WWI. When, on November 11, those who fought and died in WWI are commemorated, the sanguine colour of the red poppy, a flower that grew in profusion on Flanders Fields, is a vivid reminder to the living of the cost of sacrifice in war.

At the end of the conflict, artificial replicas of the Flanders poppy were sold in Allied countries to be worn in honour of the dead. Their resistance to decay became an embodiment of everlasting memory.

 <img alt="" src="https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194084/original/file-20171109-13329-1x6k3gr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Artificial poppies left at the Waitati cenotaph in New Zealand (2009). The white poppy is used as a symbol of peace. Nankai/Wikimedia Commons, CC BY-SA

However, the red poppy was not always adopted without criticism. After 1933, in opposition to the symbolism of it, peace ceremonies appropriated the white poppy. Each flower expresses a different view on war: red embodies commemoration of sacrifice; white opposes political violence and remembers all war victims.

As living forms, as art, and as symbols, the wildflowers that soldiers encountered in WWI Europe help us negotiate the unimaginable enormity of war and deepen the solemnity of remembrance.

'We are the dead'

Among the most affecting, but least talked about, Australian war paintings that officially commemorate and remember the fallen soldiers of the First World War, is George Lambert's Gallipoli Wild Flowers (1919). Painted while Lambert served as Official War Artist, the work is unusual for the absence of soldiers' bodies shown in action or in death. Yet it alludes to both by the inclusion of an empty slouch hat and a cluster of battlefield wildflowers. At the centre of the array of blossoms is the Flanders poppy.

 <img alt="" src="https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=483&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=483&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=483&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=607&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=607&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194068/original/file-20171109-13311-aljxpg.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=607&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 George Lambert, 'Gallipoli wild flowers', oil (1919). ART02838/Courtesy of the Australian War Memorial

The painting is a floral still-life. It exudes the melancholy of life stilled, and challenges popular conceptions that flowers are feminine, passive and beautiful. If the flowers in Lambert's painting are beautiful, it is beauty tempered by the knowledge of human suffering. And they break with convention by relating to men, not women.

The dark centres of the poppies stare at us like the eyes of men who fought at Gallipoli. The message they communicate is the same one relayed by poppies in the lines of John McCrae's mournful poem In Flanders Fields (1915): "we are the dead".

Other Australian artists deployed by the Australian War Memorial tried to render the same power, and the same symbolisms, as George Lambert's wildflower still-life, although with less intensity. Will Longstaff, for example, painted Menin Gate at midnight (1927), a monumental commemoration to men who were buried in unmarked graves on the Western Front in which the ghosts of the dead rise up among blood red poppies that grow in the same soil where their bodies decayed.

 <img alt="" src="https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=399&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=399&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194070/original/file-20171109-13323-d1v46s.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=399&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Will Longstaff, 'Menin Gate at midnight', oil on canvas (1927). ART09807/Courtesy of the Australian War Memorial

Flowers and the battlefield

On churned up war landscapes, masses of wildflowers covered derelict tanks and blanketed the ground where the dead lay, juxtaposing cold metal and the destructive power of men with the organic growth and regenerative power of nature.

Such contrasts presented Frank Hurley, Australia's Official War Photographer working in Flanders and Palestine from August to November 1917, with many of the war's most powerful images. Hurley could not ignore the cruel irony of all that fragile beauty growing free in the midst of industrialised warfare, mass killing, and the corpses of the dead.

Hurley's Lighthorseman gathering poppies, Palestine (1918) is a rare colour photograph from the period. Hurley well understood the power of the poppy. He knew that for the image to become a national icon of comradeship, the flowers had to be coloured red because it is the poppy's redness that made it the official symbol of sacrifice. Yet Hurley's photo is pastoral, and in its vision of ideal life suggests the antithesis of war.

 <img alt="" src="https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/194074/original/file-20171109-13296-93tgbc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Frank Hurley, Australian lighthorseman gathering poppies, colour photograph (c1918). PO3631.046/Courtesy of the Australian War Memorial

It may also be that flowers have a particular power over our perception. Elaine Scarry argues that the high colouration of a flower's face is more perfect for imagining and storing images to memory than the faces of people. Official and unofficial WWI records lend support to Scarry's theory.

When Cecil Malthus, a New Zealand soldier at Gallipoli in 1915, found himself under attack, it was not the faces of the soldiers around him that he remembered, but the faces of self-sown poppies and daisies on the ground.

Ann Elias ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 The wildflowers that WWI soldiers encountered in Europe become symbols of remembrance and the fragility of life. The red poppy in particular is a powerful motif in Australian war art and photography. Ann Elias, Associate Professor, Department of Art History, University of Sydney Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/81861 2017-08-01T15:09:04Z 2017-08-01T15:09:04Z Revealed: the first ever flower, 140m years ago, looked like a magnolia

  Hervé Sauquet & Jürg Schönenberger

Although most species of plants on Earth have flowers, the evolutionary origin of flowers themselves are shrouded in mystery. Flowers are the sexual organs of more than 360,000 species of plants alive today, all derived from a single common ancestor in the distant past. This ancestral plant, alive sometime between 250m and 140m years ago, produced the first flowers at a time when the planet was warmer, and richer in oxygen and greenhouse gases than today. A time when dinosaurs roamed primeval landscapes.

But despite the fact dinosaurs went extinct 65m years ago we have a better idea of what an Iguanodon looked like than of how the ancestral flower was built.

 <img alt="" src="https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=818&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=818&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=818&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1029&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1029&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180402/original/file-20170731-22126-8ddii2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1029&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 The oldest flowering fossil, a 130m-year-old aquatic plant found in modern day Spain. Gomez et al / PNAS

This is partly because these first flowers left no traces. Flowers are fragile structures that only in the luckiest of circumstances can be transformed into fossils. And, as no fossil has been found dating back 140m or more years, scientists have only had a limited sense of what the ultimate ancestor would have looked like. Until now.

A major new study by an international team of botanists has achieved the best reconstruction to date of this ancestral flower. The research, published in Nature Communications, relies not so much on fossils as on studying the characteristics of 800 of its living descendant species.

By comparing the similarities and differences among related flowering plants, it is possible to infer the characteristics of their recent ancestors. For example, because all orchid species have flowers in which one half is the mirror image of the other (bilateral symmetry), we can suppose that their ancestor must have had bilateral flowers. By comparing those recent ancestors to each other it is then possible to go a step further back in time, and so on, until eventually we reach the base of the flowering plants' family tree.

 <img alt="" src="https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180559/original/file-20170801-29610-1vb00ce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Orchids are symmetrical. Joanna Dineva

So what did it look like?

In some respects, the original flower resembles a modern magnolia: it has multiple, undifferentiated "petals" (technically tepals), arranged in concentric rings. At its centre there are multiple rows of sexual organs including pollen-producing stamens and ovule-bearing ovaries. It is hard to resist the temptation to imagine ancient pollinators crawling in this flower, collecting pollen grains while unknowingly helping the plant to produce seeds.

 <img alt="" src="https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=477&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=477&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=477&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=600&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=600&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180408/original/file-20170731-22181-12cxw50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=600&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 The ancestor of magnolia. And oak trees, grass, tomatoes, daffodils, and much more. Hervé Sauquet & Jürg Schönenberger

A controversial sex life

The new study helps to settle the controversy about whether early flowers had separate sexes, or whether both male and female reproductive organs were combined in the same flower. Previous evidence pointed to different answers. On the one hand, one of the earliest diverging lineages of flowering plants, represented nowadays only by a rare shrub from the Pacific island of New Caledonia called Amborella, has flowers that are either male or female. On the other, most modern species combine both sexes in the same flower.

 <img alt="" src="https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=576&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=576&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=576&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=724&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=724&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180553/original/file-20170801-11960-18r0ips.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=724&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 All living flowers ultimately derive from a single ancestor that lived about 140m years ago. Hervé Sauquet & Jürg Schönenberger

The authors of the study settle the question and show that the ancestral flower was a hermaphrodite. This means that early flowering plants could reproduce both as a male and a female. Combined sexes can be advantageous when colonising new environments as a single individual can be its own mate, and indeed many plant species colonising remote oceanic islands tend to be hermaphrodite. Maybe the combination of sexes helped early flowering plants to outcompete their rivals.

The devil's in the detail

Despite the apparent similarity with some modern flowers, their ultimate ancestor has a few surprises up its sleeve. For example, botanist have long thought that early flowers had floral parts arranged in a spiral around the centre of the flower as can be seen in modern species such as the star anise.

The new reconstruction, though, strongly suggests that early flowers had their organs arranged not in a spiral, but in series of concentric circles or "whorls", as in most modern plants. The early flower had more numerous whorls, however, suggesting flowers have become simpler over time. Paradoxically, this simpler architecture may have given modern plants a more stable base upon which to evolve and achieve more complex tasks such as sophisticated interaction with certain insects as in orchids, or the production of "flower heads" made of dozens or hundreds of simpler flowers as in the sunflower family.

Although now we have a good idea of what one of the earliest flowers may have looked like, we still know little about how that flower came to be. The detailed steps leading to its evolution are unknown. Perhaps we will have to wait for the discovery of new fossil flowers spanning the gap around 250m-140m years ago, before we can understand the very origin of what is the most diverse sexual structure on the planet.

Mario Vallejo-Marin ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 Scientists have reconstructed the common ancestor of everything from rose bushes to oak trees, ivy or wheat. Mario Vallejo-Marin, Associate Professor in Evolutionary Biology, University of Stirling Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/81140 2017-07-26T14:40:27Z 2017-07-26T14:40:27Z The common herb that could bring bees buzzing to your garden

  *Psyche Delia*/Flickr, CC BY-NC

Unlike parsley, sage, rosemary and thyme, wild marjoram missed out on a role in the classic song Scarborough Fair, made popular in the 1960s by Paul Simon. But it does have a key additional advantage over most herbs. People know it best under its widely-used alternate name of oregano, which is also the scientific name – origanum vulgare. It is a common feature of Italian cooking and a native around Europe and in the UK. More importantly though, it is one of the best of all plants for attracting bees, butterflies and other pollinators to your garden.

The most widely grown and appreciated garden favourites, of course, are those with attractive flowers. And there is a common assumption that those plants which delight human eyes will also be the most attractive for bees and other flower-visiting insects. Research at the Laboratory of Apiculture and Social Insects at the University of Sussex can give a more empirical take.

One project carried out in 2011-2012 saw 32 varieties of summer flowering garden plants grown in beds and counted the insects visiting them – 87% of which were bees. The plants selected were all summer-flowering varieties often grown in gardens.

All were attractive to the human eye. However, they were very different as far as the insects were concerned. The most attractive to them were marjoram and agastache, a herbaceous perennial with simple, aromatic leaves and small flowers in dense spikes. These two had 100 times as many insects as the least popular, the pelargonium, which belongs to a large group of frost-sensitive plants used for summer bedding.

Making a difference

It is a simple lesson. By choosing suitable varieties to provide nectar and pollen, gardeners can make a big difference. Our research show that helping bees and flower-visiting insects needn't come at a cost. In a 2012 survey of over 200 varieties of asters, also known as Michaelmas daisies, at the British National Collection in Picton Gardens, Herefordshire, the varieties that attracted more insects were just as easy to obtain, easy to grow, and attractive to the human eye. Prices are similar, although that depends mainly on the size of the plant when you buy it.

So, how good for insects are the flowers grown in parks and gardens? In the East Sussex town of Lewes there is a beautiful park, Southover Grange Garden, which is carefully managed to provide magnificent floral displays in spring and summer. We counted the insects on 79 varieties in full bloom in August 2012.

The results were surprising. The park appeared to be a bee paradise, but only three of the varieties were highly attractive to flower-visiting insects. On 24 varieties we saw no insects in any of the 15 counts made, and on a further 37 there were very few. Clearly, there is room for improvement. Many garden flowers are more show than go: bred for many bright petals instead of food for the bees.

 <img alt="" src="https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178625/original/file-20170718-31872-1k7ln8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Southover Grange Gardens in Lewes. Leonora (Ellie) Enking/Flickr, CC BY-SA

Turning over a new leaf

Many gardeners in the UK get their plants from one of more than 2,000 garden centres and retail nurseries. They are popular destinations for plants and equipment (and for a cup of tea and a slice of cake). They play an important role in what British gardeners end up growing and what insects will be able to visit.

Garden centres normally sell plants in bloom with each variety in a distinct patch. This makes it easy to monitor the insects. In 2015 we counted the insects on the 59-74 plant varieties in full bloom on sale in five garden centres and one nursery in Sussex. We made 12 counts over one day in each. We even brought in our own marjoram plants to set up two comparison patches of a variety we knew to be very attractive.

We found a similar pattern to that seen in the other two studies. Most varieties on sale had few bees and other insects, and a small number had many. Our marjoram did well, as expected, but 4.5% of the plants on sale turned out to be even more attractive, with an average of 26% more insects. Strong performers included the deep magenta flowers of cosmos bipinnatus "Sonata Carmine" and caryopteris x clandonensis "Heavenly Blue", a compact shrub with clusters of dark blue flowers.

 <img alt="" src="https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178652/original/file-20170718-10331-uzee8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Garden centres: on the front line. muffinn/Flickr, CC BY

Some of the plants on sale, about 15%, were marketed as bee-friendly, and just over half of those appear on the Royal Horticultural Society's "Perfect for Pollinators" list. How good were these? Well, the average looks good: recommended plants attracted three times as many flower-visitors as the rest. However, many plants in that group were unattractive to insects or underperformed. Equally, some non-recommended varieties such as iberis "Masterpiece" and alstromeria "Inticancha Dark Purple" did really well. The labelling appears to be inconsistent and certainly over-optimistic. Perhaps "better for pollinators" would be more accurate.

Our research shows that the public could be making their gardens much more attractive to bees and other insects simply by more careful flower choice. And garden centres can be part of this, by improving stocks and by educating customers to favour more of the highly attractive varieties.

Many of the plants of the family lamiaceae, the mint family, are great for pollinators. That includes marjoram as well as thyme, lavender and Russian sage (perovska). Others, such as heleniums and some dahlias are in the daisy family. Different varieties bloom at different times, and can provide valuable additional food across the whole summer to a whole range of flower-visitors.

If you want to help bees and other insects in your garden, have a look round your garden centre on a sunny summer day. Plants with 10 insects, even five, per square metre when in full bloom are the ones to go for. But don't buy a plant that you don't like. There are plenty of bee-friendly varieties, so a win-win situation is possible: chose plants that you – and the bees – both love.

Karin Alton would like to acknowledge Mihail Garbuzov for his contribution to the research.

Francis Ratnieks ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 Garden pollinators can turn their noses up at the flowers human eyes find most beautiful. Karin Alton, Research Fellow Apiculture, University of Sussex Francis Ratnieks, Professor of Apiculture, University of Sussex Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/74086 2017-04-10T07:18:31Z 2017-04-10T07:18:31Z Bloomageddon: seven clever ways bluebells win the woodland turf war

'This is our patch.' Shutterstock

The appearance of vivid bluebell carpets in British woodlands is a sure and spectacular sign of spring. Bluebells – Hyacinthoides non-scripta (L.) Chouard ex Rothm – are Britain's favourite wildflower and particularly fine carpets attract visitors to well-known sites such as Kew Gardens in London and Coed Cefn in Powys, Wales.

Bluebells also form carpets without a wooded canopy – for example, on Skomer Island in Wales – and point to the locations of ancient forests, long after the trees themselves have vanished. This is because, unlike trees, bluebells have most of their biomass and reproductive organs (the bulb) below ground where they are better protected.

They certainly are worth treasuring. It is estimated that Britain is home to half the world's population of bluebells. But they are now threatened by the introduction of the related Spanish bluebell, (Hyacinthoides hispanica), leading to hybridisation and loss of habitat. Once removed, it takes decades to establish a population of bluebells large enough to create the characteristic carpets.

They are beautiful flowers, but have you ever wondered how bluebells pull off an even more impressive feat: being in their flowering prime when other plants have only just started to grow? Here are seven of their cleverest tricks.

1) The cold triggers growth: While most plants require a number of hours above a certain temperature before they start growing again, bluebells are dormant during the heat of the summer. Instead, their seeds are triggered to germinate when the temperature drops below 10°C, allowing them to get a vital head start and be in full bloom when spring finally arrives.

 <img alt="" src="https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159549/original/image-20170306-20749-1dgxh81.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Cool customer: bluebells start growing when the temperature falls. Shutterstock

2) They dig deep: Bluebells have contractile roots, which pull the bulb deeper and deeper into the soil with every year of growth. This protects the bulb from frost, which starts from the soil surface, and temperature fluctuations, and provides better access to water in drought conditions.

3) They use fructans as reserve carbohydrates: While most plants use glucose and build starch or cellulose, bluebells predominantly convert sunlight into fructose, from which they build fructans. This adaptation allows them to photosynthesise at temperatures below 10°C. The plant's large bulb comprises up to 70% fructans, which fuels their winter growth.

Fructans also serve another purpose, minimising the formation of new cells and causing existing cells to elongate instead. This is an advantage because the plants can grow without biosynthesising all the material needed to make new cells. You can see the effects of this by looking at a bluebell's leaves: at first, they are firm and upright, but gradually lose their rigidity as the cells elongate.

4) They spear through any obstacles: The leaves that emerge from the bulb are as close to each other as possible and shaped like a spear with a small, sharp tip. This allows them to find their way through any obstacle – both below and above ground. When the leaves start emerging in mid-winter, there tends to be a lot of dead leaf matter and other detritus lying on the forest floor. Having an arsenal of little spears is critical for punching your way through this into the sunlight.

Bloomin' clever

 <img alt="" src="https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/159551/original/image-20170306-20746-1yte7hc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Bluebells at the base of an old oak tree. Shutterstock

5) They cooperate: Bluebells are known to cooperate with mycorrhiza – symbiotic fungi. The fungi obtains carbon from the bluebell in exchange for nutrients, particularly phosphorus. Both parties win, thanks to their use of a wood wide web.

6) … and compete: Phosphorus is an important resource for plants – and bluebells "know" it. As well as securing their supply of it with the help of mycorrhiza, they also restrict the supply available to other plants. They do this by storing phosphorus in the form of phytate, which can only be converted into a usable form with specialised enzymes.

7) They shape their surroundings: Bluebells engineer the soil and their environment to optimally support their own kind while making it harder for other species to grow. As well as storing phosphorus in the form of phytate, and using fructans instead of glucose-based polymers, they quite literally win the turf war by carpeting the space above ground.

Vera Thoss is director of Vera Bluebell limited.
 They're not just a pretty spring sight – behind the scenes, bluebells are ruthless competitors. Vera Thoss, Lecturer in Chemistry, Bangor University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/68736 2016-11-15T19:06:47Z 2016-11-15T19:06:47Z National parks are vital for protecting Australia's endangered plants

There are fewer than a thousand Graveside gorge wattles in Kakadu National Park. Parks Australia

Norfolk Island, nearly 1,500km from Australia's east coast, is home to one of the country's most endangered species, but you probably haven't heard of it. Clematis dubia, a woody climber with white and hairy flowers, was known to number only 15 mature plants in 2003.

Once common on the island, this clematis illustrates what stands in the way of survival for many of our threatened plants. Around 84% of Australia's native plants don't occur anywhere else on Earth.

Threats to our native plants include ongoing habitat destruction, fire, invasive species, more frequent extreme weather events, and declining populations of the animals involved in their pollination and seed dispersal.

Clematis dubia is lucky to call Norfolk Island National Park home. Our national parks are places of beauty and adventure for us to enjoy. They are also a haven for many species.

But life in a national park doesn't guarantee a species' survival. Recently we assessed 41 endangered or significant plants that occur in Australia's six Commonwealth National Parks, to identify ways to help these plants recover.

We found that many of these species don't occur outside national parks, meaning the parks play a huge role in their conservation. Few of these species have been secured in living plant collections or seed banks, and very few are regularly monitored in the wild.

We have little information on either the impacts of threats or of species biology, which limits our ability to secure these species against further loss.

 <img alt="" src="https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145723/original/image-20161114-9060-180k421.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 There were only 15 mature Clematis dubia on Norfolk Island known in 2003. Parks Australia

Threats to plants

Clematis dubia lives in small and isolated populations. It faces many perils of modern life, like invasive weeds. We understand very little of its biology, including how its seeds are dispersed, how long it takes to start producing seed, and even how long it lives.

Another plant we assessed was the Graveside Gorge wattle (Acacia equisetifolia) found in Kakadu National Park. A small shrub, less than a metre tall with small yellow flowers, this wattle is listed as critically endangered.

Fewer than a thousand plants are growing in only two locations about a kilometre apart in a restricted area of the park. There is little information on the basic biology of this shrub.

Like other acacias, Graveside Gorge wattle is probably pollinated by, and provides food for, a variety of different insect species. It probably only reproduces sexually and its seeds might be dispersed by ants and probably germinate after fires. The main threat to this species is fires, especially ones that are too frequent or too intense.

As a safeguard against extinction, Parks Australia has collected seed from the Graveside Gorge wattle, which is now stored in the National Seed Bank at the Australian National Botanic Gardens in Canberra.

 <img alt="" src="https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=551&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=551&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=551&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=692&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=692&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145722/original/image-20161114-9073-1ufjwon.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=692&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Hibiscus brennanii is a vulnerable shrub found in Kakadu National Park. Parks Australia

 <img alt="" src="https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/145721/original/image-20161114-9081-nuab1b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Jenny Hunter, Kakadu ranger, collecting Hibiscus brennanii seed for the seed bank. Parks Australia

Seed banking can extend the longevity of seeds to hundreds of years, protecting a species from extinction and helping in its recovery should the worst happen. Germination trials at the National Seed Bank help unlock the often complex germination requirements of different species so that they can be regrown from seed.

As a result of trials with Graveside gorge wattle, the Gardens now has a living collection of this species. In Kakadu, Parks Australia is protecting the two wild populations by planning protective burning to create longer intervals between fires and reduce the likelihood of severe fires.

Protecting plants

Seed banking and living collections are two of the strategies we recommended to safeguard populations of threatened plant species. Some species may also benefit from establishing new populations outside national parks, similar to the management strategies used for vertebrate animals.

We also recommend surveying all endangered plant species in national parks that are not currently part of a formal monitoring program or that have not been surveyed within the past two years.

Finally, realising the gaps in our knowledge of the biology of and threats to many of Australia's threatened plants, we recommend partnering with researchers and NGOs with restoration experience to draw on available scientific and on-the-ground knowledge.

And what of Norfolk Island's endemic climbing clematis, Clematis dubia? Along with the low number of individuals, competition from weeds is a major threat to the survival of this species, so conservation efforts by Parks Australia have involved intensive weed control work, particularly to deal with the invasive guava plant.

Recent searches in likely habitat have revealed an additional 33 plants, a mix of adults and juveniles. Happily, new seedlings are now showing up in areas where guava has been removed, improving the future prospects for this species.

The report Constraints to Threatened Plant Recovery in Commonwealth National Parks was funded by the Australian Government through the Threatened Species Commissioner, Gregory Andrews. It was authored by researchers at the Centre for Australian National Biodiversity Research, a joint initiative between Parks Australia's Australian National Botanic Gardens and CSIRO.

Linda Broadhurst receives funding from the Threatened Species Commissioner and the Australian Commonwealth Government. She is affiliated with the Australian Network for Plant Conservation.
 We know very little about Australia's most threatened plants. Linda Broadhurst, Director, Centre for Australian National Biodiversity Research, CSIRO Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/59504 2016-05-24T09:49:25Z 2016-05-24T09:49:25Z The flower breeders who sold X-ray lilies and atomic marigolds
The Chelsea Flower Show, one of the biggest and best known horticultural shows in the world, is now open. In the coming days, some 150,000 visitors will make their way to the Royal Hospital Chelsea, expecting to be wowed by innovative garden designs and especially by gorgeous flowers. Among other things, show-goers will have a chance to learn the winner of the Royal Horticultural Society's Plant of the Year award. This annual prize goes to the "most inspiring new plant" on display at the show – a high honour indeed given the number and range of varieties introduced each year.

The relentless pursuit of showy flowers for garden display extends back significantly further than the 104 years of the Chelsea show. One need only recall the infamous Dutch tulip craze of the 17th century to be reminded that fascination with floral novelties has a long and storied history.

Over the centuries, entrepreneurial cultivators have endeavoured to create unique plant varieties, either by bringing together the genetic material from established lines through hybridisation or through the discovery of new genetic variation such as a chance mutation in a field. Today, flower breeding is pursued with a far better understanding of plant biology than ever before, in some cases with the aid of technologies such as tissue culture and genetic transformation. Yet the goal remains the same: the creation of tantalising tulips, ravishing roses, show-stopping snapdragons and myriad other plants that will ideally prove irresistible to gardeners and turn a handsome profit.

The quest to produce profitable new varieties – and to do so as fast as possible – at times led to breeders to embrace methods that today seem strange. There is no better illustration of this than the mid-century output of one of America's largest flower-and-vegetable-seed companies, W Atlee Burpee & Co.

Gardening with X-rays

In 1941, Burpee Seed introduced a pair of calendula flowers called the "X-Ray Twins". The company president, David Burpee, claimed that these had their origins in a batch of seeds exposed to X-rays in 1933 and that the radiation had generated mutant types, from which the "X-Ray Twins" were eventually developed.

At the time, Burpee was not alone in exploring whether X-rays might facilitate flower breeding. Geneticists had only recently come to agree that radiation could lead to genetic mutation: the possibilities for creating variation "on demand" now seemed boundless. Some breeders even hoped that X-ray technologies would help them press beyond existing biological limits.

The Czech-born horticulturist Frank Reinelt thought that subjecting bulbs to radiation might help him produce an elusive red delphinium. Unfortunately, the experiment did not produce the hoped-for hue. Greater success was achieved by two engineers at the General Electric Research Laboratory, who produced – and patented – a new variety of lily as a result of their experiments in X-ray breeding.

Though Reinelt's and other breeders' tangles with X-ray technology resulted in woefully few marketable plant varieties, David Burpee remained keen on testing new techniques as they appeared on the horizon. He was especially excited about methods that, like X-ray irradiation, promised to generate manifold genetic mutations. He thought these would transform plant breeding by making new inheritable traits – the essential foundation of a novel flower variety – available on demand. He estimated that "in his father's time" a breeder chanced on a mutation "once in every 900,000 plants". He and his breeders, by comparison, equipped with X-rays, UV-radiation, chemicals, and other mutation-inducing methods, could "turn them out once in every 900 plants. Or oftener".

Scientific sales pitches

 <img alt="" src="https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=930&fit=crop&dpr=1 600w, https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=930&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=930&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1169&fit=crop&dpr=1 754w, https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1169&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/123630/original/image-20160523-11025-1sr1nq4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1169&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A 1973 Burpee cover. Burpee, CC BY-NC-ND

Burpee's numbers were hot air, but in a few cases plant varieties produced through such methods did prove hot sellers. In the late 1930s Burpee breeders began experimentation with a plant alkaloid called colchicine, a compound that sometimes has the effect of doubling the number of chromosomes in a plant's cells. They exploited the technique to create new varieties of popular garden flowers such as marigold, phlox, zinnia, and snapdragons.

All were advertised as larger and hardier as a result of their chromosome reconfiguration – and celebrated by the company as the products of "chemically accelerated evolution". The technique proved particularly successful with snapdragons, giving rise to a line of "Tetra Snaps" that were by the mid-1950s the best-selling varieties of that flower in the United States.

Burpee's fascination with (in his words) "shocking mother nature" to create novel flowers for American gardeners eventually led him to explore still more potent techniques for generating inheritable variation. He even had some of the company's flower beds seeded with radioactive phosphorus in the 1950s. These efforts do not appear to have led to any new varieties – Burpee Seed never hawked an "atomic-bred" flower – but the firm's experimentation with radiation did result in a new Burpee product. Beginning in 1962, they offered for sale packages of "atomic-treated" marigold seeds, from which home growers might expect to grow a rare white marigold among other oddities.

Burpee was, above all, a consummate showman and a master salesman. His enthusiasm for the use of X-rays, chemicals, and radioisotopes in flower breeding emerged as much from his knowledge that these methods could be effectively incorporated into sales pitches as from his interest in more efficient and effective breeding. Many of his mid-century consumers wanted to see the latest science and technology at work in their gardens, whether in the form of plant hormones, chemical treatments, or varieties produced through startling new techniques.

Times have changed, 60-odd years later. Chemicals and radiation are as more often cast as threatening than benign, and it is likely that many of today's visitors to the Chelsea Flower Show hold a different view about the kinds of breeding methods they'd like to see employed on their garden flowers. But as the continued popularity of the show attests, their celebration of flower innovations and the human ingenuity behind these continues, unabated.

Helen Anne Curry ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.
 The relentless pursuit of showy flowers for garden display – as seen at Chelsea Flower Show – has seen some odd uses of radiation and chemicals . Helen Anne Curry, Peter Lipton Lecturer in History of Modern Science and Technology, University of Cambridge Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/46311 2016-03-29T09:26:58Z 2016-03-29T09:26:58Z No garden? Five creative ways city dwellers can still grow their own
With more people than ever living in cities, how do we reconcile our need for fresh fruit and vegetables with the challenges of life in an urban environment where the time and space for gardening are limited?

Thankfully, there are many ways to grow your own fresh produce in the city, which go beyond the traditional solution of the allotment. Here are just five:

1. Create your own window farm

Here's proof that you can grow food in the smallest and most urban of settings. Window farming allows you to grow plants vertically inside your house or flat with the roots resting in water with added nutrients, a system called hydroponics. There's no need for outdoor space or even any soil.

These "farms" can be as complex or simple as you like and there are now more than 45,000 window farmers around the world collaborating to find new ways of growing food.

 <img alt="" src="https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=323&fit=crop&dpr=1 600w, https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=323&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=323&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=406&fit=crop&dpr=1 754w, https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=406&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/111522/original/image-20160215-8211-1fk6zh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=406&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Save space by going soil-free. Jon Kalish, CC BY-SA

2. Guerrilla gardening

At its most basic, guerrilla gardening involves the cultivation of land that you have no legal right to use. As such, it's about much more than growing fruit and veg, since projects tend to have broader aims to do with reclaiming public space and transforming derelict or neglected parts of the urban landscape.

At its best, it is a creative and inspiring example of direct action. Think of "seed bombs" used to transform a demolition site into a haven for pollinating insects, or lavender and sunflowers being added to a traffic island under cover of night.

3. Join a community garden

Unlike allotments, community gardens are focused on doing things together with others. They're perfect for people who don't have the time or skills required to work an allotment on their own, and the the camaraderie of working together and learning from more experienced gardeners provides huge social benefits beyond the food they produce.

 <img alt="" src="https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93163/original/image-20150827-381-1hrxva2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 The Gardens Community Garden in Haringey. DCLG, CC BY-ND

4. Community-supported agriculture

So-called "CSA" projects are still relatively new in the UK but the idea behind them is simple: to create a direct connection between farmers and consumers and take back control of the food system from supermarkets and large corporations. Some schemes are similar to existing veg box delivery services where you simply pay to sign up and receive regular vegetable deliveries in return.

However, others allow you to be much more than just a "consumer" as you spend time working on the farm in exchange for produce. In this way, you can get some fresh air and exercise while learning new skills and meeting like-minded people. From the farmer's perspective this also means a guaranteed market and extra help on the farm. Interested? You can find your local scheme here.

 <img alt="" src="https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/93166/original/image-20150827-372-1y0rdwk.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 You can be a 'producer' as well as a consumer. www.shutterstock.com

5. Urban foraging

Do you like the idea of finding your own food but you're not keen on gardening? No problem. If you know where to look, urban areas also offer plenty of opportunities to find good food for free.

Parks, cemeteries and neglected canal towpaths often offer lots of edible species, from the relatively common blackberry and elderberry to more unusual tasty treats that you can use to spice up your meals. For example, hedge garlic – or Jack by the hedge – can be a fantastic addition to salads, while hawthorn berries and crab apples can make a fabulous jam.

 <img alt="" src="https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/116038/original/image-20160322-32312-1a48hif.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 Found in shady urban wastelands, 'Jack by the hedge' is delicious in salads. Nick Saltmarsh, CC BY

Of course, you need to be careful about possible contamination or misidentification but, if you're unsure, why not see if your city has a forage walk that you can join? That way, you can learn first-hand about what's safe to eat.

Shops, supermarkets and restaurants also throw out lots of perfectly edible food every day. An increasing number of people are foraging in bins for bread, tinned beans or even beer. This hunt for ready-made food is known as "skipping" or "dumpster diving". Like many of the other methods described here, it's not just a means of feeding yourself but a political act that highlights the wastefulness of the global food system.

Rebecca Whittle is a member of The Green Party. This article does not reflect the views of the research councils or other public funders.
 Essential reading for green-fingered urbanites and guerrilla gardeners. Rebecca Whittle, Lecturer, Lancaster Environment Centre, Lancaster University Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/52373 2016-01-25T19:17:38Z 2016-01-25T19:17:38Z Not just bees: the buzz on our other vital insect helpers

A hoverfly on a sunflower.  David Kleijn

We hear a lot about bees and how important they are for growing our crops. Well, they are – and we should also be concerned about recent declines in bee populations and their health.

But bees aren't the only pollinators. Our recent global analysis has revealed that the "non-bee" insects are playing much bigger roles than had been appreciated.

These wild insect pollinators occur naturally in our crops and are not deliberately managed by growers. Among the important insects are bees, flies, beetles, butterflies, moths and wasps.

We know that these other pollinators can be very important. For instance, the contribution by wild pollinating insects other than bees in oilseed rape in Sweden varied from 5-80%.

In Australia, we're not so sure. We need to make sure that in our focus on bees, we don't ignore our other pollinators.

Pollination makes the world go 'round

Overall, about three-quarters of all the world's food crops and a third of the food we eat by volume, comes from pollinator-dependent crops.

Different crops vary in their need for animal pollination. Some crops, such as almonds, melons and passionfruit need pollination in order to produce their fruits or nuts, while others like carrots and onions, need pollination only for seed production.

In Australia we grow a huge range of crops in environments ranging from tropical to cooler climates. We are the world's second largest exporter of canola and grow this crop across much of the southern half of the continent (in every state except the NT) and we also produce tropical crops such as mango that can grow across much of the top half of the country.

For every crop there can also be a range of different varieties, which can vary in how much they depend on pollinators.

A couple of recent studies have shown that the ubiquitous European honey bee underperforms compared to other species when it comes to pollination.

For example, research on blueberry in North America has found that some wild bee species visit more flowers and transfer more pollen between flowers, compared to honey bees.

The 'other pollinators'

Most crop pollination studies focus on bees (domesticated and wild) because they have the strongest biological association with flowers.

Our recent study revealed that the contribution by pollinators other than bees varied a lot within and among crops and locations.

So what does this mean for Australian crops?

Well, we don't know which pollinators visit every Australian crop in every growing region and we can't predict what the pollinator community will be. This is a huge knowledge gap considering that wild pollinators contribute so much to crop pollination generally.

We know a little about custard apples, almonds, mangos, canola and a few other crops but have little idea of who are the pollinators for many other pollinator-dependent crops in Australia, let alone variation in what type of pollinators are found where and with which other pollinators.

Looking after our pollinators

We know that bees need somewhere to make their nests, as well as flowers to feed their young. Because of these needs, natural habitats such as trees and other woody vegetation are often associated with more bees visiting crops and more different species of bees.

Yet, we know very little about how habitat affects crop pollination from insects other than bees. Flies and beetles have quite different adult and larval stages, which usually have quite different resource needs.

For example, hoverflies can feed on aphids or decaying plant matter as larvae and then need nectar and pollen as adults. Understanding what these pollinators need will help us protect them and manage them better on farms.

In Australia, we have few measures for growers to protect habitats and manage biodiversity.

In Europe schemes provide payments to farmers in return for a service of benefit to biodiversity and conservation. These schemes include creating wildflower strips, reducing the use of chemicals, organic farming, converting farmland to grassland, cover crops, buffer strips, reducing water use, and maintaining landscape features (such as isolated trees, hedges and stone walls, allowing public access, set asides). Farmers sign a contract and are paid for the cost of meeting certain commitments, and compensated for any losses of income due to reduced production. Like most land management initiatives, these schemes have their share of challenges, but targeted schemes can have positive benefits for crop yields and wild pollinators.

We still have a lot of knowledge gaps to fill, but we are also in a great position to do this. Australia's pollinator insect fauna is unique and diverse. Investing in building our knowledge of these species and their ecology will ease the pressures on our managed honey bees and have ongoing biodiversity and crop production benefits across Australia.

Romina Rader receives funding from the University of New England, the Ian Potter Foundation and the New Zealand Institute for Plant and Food Research. She is affiliated with the University of New England, Armidale, Australia.

Manu Saunders is affiliated with Institute for Land Water and Society, Charles Sturt University.

Saul Cunningham receives funding from Horticulture Innovation Australia to support pollination research. He is employed by the CSIRO.
 Next time you reach for the honey, spare a thought for the other vital insects that pollinate our crops. Romina Rader, Lecturer in Community Ecology, University of New England Manu Saunders, Post-doctoral Research Fellow (Ecology), Charles Sturt University Saul Cunningham, Researcher, CSIRO Licensed as Creative Commons – attribution, no derivatives. tag:theconversation.com,2011:article/23659 2014-02-26T01:55:58Z 2014-02-26T01:55:58Z Colourful language – it's how Aussie birds and flowers 'speak'

Australian flowers and their pollinators have evolved a specific way of communicating – all based upon colour. aussiegall/Flickr, CC BY-SA

In Australia, honeyeaters are far and away the most abundant and important nectar-feeding birds, so also the most important avian pollinators of flowers.

What effect has their visual perception had on the evolution of colour among the flowers they visit?

Today, a team of biologists from Monash (including me) and RMIT universities in Melbourne and Bucknell University in the US published the most quantitative and rigorous investigation of this question to date.

We used mathematical models of bird vision to represent the colours of Australian flowers as birds are likely to see them.

Reading colours

Birds and flowers provide much of the colour that we see in the natural world, but we are accidental eavesdroppers on the visual conversations in which they are engaged:

colourful birds signal not to us but to potential mates

colourful flowers also try to find mates, but they do so by communicating first to animal pollinators, including many birds.

 <img alt="" src="https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/42501/original/sbkjvq89-1393370707.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
 A New Holland honeyeater (Phylidonyris novaehollandiae) visiting flowers of Banksia menziesii (Proteaceae). Mani Shrestha

Biologists have long wished to know how visual communication between flowers and their pollinators works, but it's not an easy task as animals perceive colours quite differently from us.

We humans have three types of colour receptors in our retinas, sensitive to blue, green, and red light.

Birds have four types of receptors, and see more complexity in colours than we do. Some birds, including the honeyeaters, have violet-sensitive receptors along with blue, green and red receptors. Other birds use receptors sensitive to ultraviolet rather violet light.

In our study, we examined the reflectance profiles (patterns of how an object reflects light of different wavelengths) of the flowers of 234 native Australian species.

We measured these profiles across the ultraviolet and visual wavelengths of light, and these profiles were then translated into single points in a "colour space" based on the sensitivities of birds' four classes of colour receptors. (A colour space is a way of positioning reflectance profiles within a four-dimensional grid so that colours lying near each other would appear similar to a bird.)

Of the 234 plant species we looked at, 154 were pollinated by insects and 80 by birds. The insect-pollinated flowers had a colour range that we see as violet and blue to yellow. Although birds don't pollinate these flowers, birds would also see them as having a broad range of colours.

The flowers that were bird-pollinated formed a more interesting pattern. About half the species overlapped with the colour space arc of insect-pollinated flowers. As bird pollination usually evolves from insect-pollinated ancestors, this similarity in colours is not surprising.

The other half of bird-pollinated species, however, were crowded in a narrow and separate stretch that occupied just 1% of the total volume of the colour space. These flowers appear red to humans, and we named this cluster the "red arm". Their reflectance profiles would also strongly stimulate the red receptors in bird eyes.

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 A New Holland honeyeater (Phylidonyris novaehollandiae) visiting flowers of Eremophila maculata (Scrophulariaceae). Mani Shrestha

It appeared that many flowering species had evolved to "talk" to birds using a very particular set of colour "words". In particular, the distinctiveness of the "red arm" appeared only when the colour space was based on the visual system of honeyeaters.

Models of the other visual system in birds with ultraviolet receptors, common in parrots and songbirds, did not reveal a distinctive red arm of floral colours.

'Language' evolution

Evolution could produce this shared use of a special colour language in two ways. Plants that evolved a red-arm colour might speciate more frequently, perhaps because of their special appeal to honeyeaters, thus creating a "radiation" of lineages that use the distinctive colours, somewhat like a family that occasionally uses their own special words rather than standard English.

Alternatively, many unrelated lineages may get in on the act by independently evolving the red-arm colours. Because evolutionary relationships among plant species are now fairly well understood thanks to DNA sequence evidence, we were able to test these alternatives.

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 A sunbird (Cinnyris pulchellus). jvverde/Flickr, CC BY-NC

Using new statistical techniques developed at Bucknell University, we showed that the distinctive red-arm colours had probably evolved on 31 separate occasions.

We could also show that had floral colours evolved as a random walk through the colour space, the red arm colours would have evolved, on average, only five or six times.

This is strong quantitative evidence of convergent evolution, the repeated appearance of the same or similar traits among unrelated lineages.

The same patterns may have evolved on an intercontinental scale. Hummingbirds, which have been exclusively in the Americas for millions of years, have a visual system with violet-sensitive receptors similar to that of honeyeaters in Australia.

In contrast, sunbirds, which are major pollinators in Africa and southern Asia, have the visual system with ultra-violet receptors.

The evolutionary convergence that shaped the red arm among Australian floral colours should, then, also appear among American plants visited by hummingbirds, but not among Asian and African species.

So is this the case? It's a question we hope to answer next.

Martin Burd was involved in the study mentioned in the article.
 In Australia, honeyeaters are far and away the most abundant and important nectar-feeding birds, so also the most important avian pollinators of flowers. What effect has their visual perception had on… Martin Burd, Associate Professor of Evolutionary Ecology, Monash University Licensed as Creative Commons – attribution, no derivatives.