Fritillaries have also been observed feeding on different thistle species, betony, and ragwort. In many Australian states ragwort has been declared a noxious weed. It will also visit flowers such as "Buddleia", ragwort, and red valerian. Horses seem to be particularly vulnerable to senecionine poisoning through ingestion of ragwort. It is variously known as the woodland ragwort, heath groundsel, or mountain common groundsel. It is known as the sticky ragwort, sticky groundsel or stinking groundsel. The danger of ragwort is that the toxin can have a cumulative effect. Horses do not normally eat fresh ragwort due to its bitter taste. The ragwort or "cushag" is the Manx national flower. The ragwort, in fact, usually has thirteen petals. This Act is amended for England and Wales by the Ragwort Control Act 2003. The biological control of ragwort was already used in the 1930s. Ragwort is native to the Eurasian continent. Ragwort is of concern to people who keep horses and cattle. Ragwort is abundant in waste land, waysides and grazing pastures.