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Flora Data (Last Modified On 1/14/2013)
Description Scandent lianas, herbs, or rarely trees, the wood often having broad inter- fascicular rays. Leaves alternate, spiral, estipulate, simple, palmately veined, usually entire. Flowers mostly axillary, perfect, actinomorphic or zygomorphic, hypogynous to epigynous, in racemes, cymes, solitary or in clusters and cauli- florous, rarely terminal, large and showy or small, often with fetid or resinous odor. Calyx gamosepalous, often petaloid and elaborately contorted and lobed. Corolla of 3 reniform petals in Saruma, rudimentary in some species of Asarum, absent in all other members of the family. Stamens 6 to 12 or occasionally many, in one or two whorls, free, connate or adnate to the short, fleshy, united styles. Ovary apocarpous to syncarpous, 6- to 4-carpellate and -loculate, with marginal to axile placentation; ovules many to few, anatropous. Pollen monosulcate to nonaper- turate, spherical. Fruit follicular or capsular with septicidal, rarely septifragal or irregular dehiscence, often dehiscing acropetally; seeds numerous to few, with a small basal embryo in abundant endosperm.
Habit lianas herbs
Habit rarely trees
Note The Aristolochiaceae, or Birthworts, are distributed throughout the tropic and temperate regions of the world. The genera are poorly defined and are in need of competent revision. The largest genus, Aristolochia, is the sole representative of the family in Panama. It is a large genus with about 300 species in tropic and temperate areas throughout the world. Eleven species are reported from Panama, but further collections will probably double this number. The leaves of Aristolochia are remarkably variable. For example, on a single shoot about 2 dm. long of Aristolochia panamensis leaves may be seen which are narrowly linear-lanceolate, broadly ovate, and broadly obtriangulate with a deeply emarginate apex. As a consequence, leaf characteristics have been used as infre- quently as possible in the keys. An exception to this general rule may be noted in that group which bears pseudostipules. The Aristolochiaceae, it will be recalled, are estipulate; however, in these species, an axillary bud produces a single, small leaf which is amplexicaul and nearly sessile. It frequently is ruffled, not having the shape of the ordinary leaves on the shoot, and looks strikingly like a pair of connate, auriculate stipules. The description of a flower as complex as that of Aristolochia is always a problem. The species differences of greatest importance lie in the elaborate inflations and expansions of the calyx tube. In an attempt to standardize the descriptions, therefore, it has seemed convenient to subdivide the calyx tube into several morphological portions and to treat each of these separately. It should be emphasized here that not necessarily all of these subdivisions are present in any given species. An explanation of these arbitrary designations follows. As the calyx arises from the apex of the ovary, it expands into a large, inflated, usually gibbous portion called the utricle. The utricle narrows into the cylindrical portion known as the tube. This expands- and usually imperceptibly merges with the expanded limb. In the larger flowers the tube has a peculiar venation at its distal end which sub- divides the tube into two portions, conveniently described as the tube proper, and the throat. The throat is usually funnelform and as a result tends to lend greater width and expansion to the limb. One constantly finds reference in the literature to the fetid odor of Aristo- lochia flowers. While many of them are truly fetid and evil smelling, many are odorless and a few have been described as having either a sweet or a resinous odor. The flowers ostensibly are pollinated by various species of Diptera. In herbarium specimens, dissection of the utricle often reveals insects which have burrowed or forced their way between the lobes of the styles. The flowers are equipped with rigid, inward-pointing hairs throughout the length of the tube. The Diptera, doubtless attracted by the color and odor of the blooms, are trapped within the utricle since they are able to pass only inward over the hairs. The flowers are protogynous. With pollination, the anthers dehisce and the rigid hairs in the tube wilt, allowing the flies to escape and carry pollen to another bloom. Several species of Aristolochia furnish the serpentaria of medicine which is used as a tonic and as a febrifuge. Many of the plants are utilized as a native remedy for snakebite and bear the common name Snakeroot. The remarkable shapes of the calyx tubes lead to various names such as Dutch- man's Pipe, Pelican Flower and Goose Flower. The name Aristolochia, which is derived from the Greek aristos, best, and lochia, delivery, refers to its supposed medicinal properties in connection with the alleviation of the pains of childbirth; the curved flower, with summit and base together suggesting, by the doctrine of signatures, the human fetus in the womb. Standley, writing about the aristolochias of El Salvador, reports that the roots of guaco or A. anguicida are used by the natives to wash clothes, to scour out dirt, and also as a remedy for stomach ache. He further states that infusions of A. arborescens are used as a remedy for venereal diseases in the female and for dysentery in children.