Aristolochia arborea

Description

Aristolochia arborea is a species of perennial plant in the family Aristolochiaceae. It is found from Mexico through Guatemala and El Salvador. Aristolochia is a large plant genus with over 500 species that is the type genus of the family Aristolochiaceae. Its members are commonly known as birthwort, pipevine or Dutchman's pipe and are widespread and occur in the most diverse climates. Some species, like A. utriformis and A. westlandii, are threatened with extinction. Isotrema is usually included here, but might be a valid genus. If so, it contains those species with a three-lobed calyx. Aristolochia is a genus of evergreen and deciduous lianas (woody vines) and herbaceous perennials. The smooth stem is erect or somewhat twining. The simple leaves are alternate and cordate, membranous, growing on leaf stalks. There are no stipules. The flowers grow in the leaf axils. They are inflated and globose at the base, continuing as a long perianth tube, ending in a tongue-shaped, brightly colored lobe. There is no corolla. The calyx is one to three whorled, and three to six toothed. The sepals are united (gamosepalous). There are six to 40 stamens in one whorl. They are united with the style, forming a gynostemium. The ovary is inferior and is four to six locular. These flowers have a specialized pollination mechanism. The plants are aromatic and their strong scent attracts insects. The inner part of the perianth tube is covered with hairs, acting as a fly-trap. These hairs then wither to release the fly, covered with pollen. The Bencao Gangmu, compiled by Li Shi-Zhen in the latter part of the sixteenth century, was based on the author's experience and on data obtained from earlier herbals; this Chinese herbal classic describes 1892 "drugs" (with 1110 drawings), including many species of Aristolochia.For 400 years, the Bencao Gangmu remained the principal source of information in traditional Chinese medicine and the work was translated into numerous languages, reflecting its influence in countries other than China. In the mid-twentieth century, the Bencao Gangmu was replaced by modern Materia Medica, the most comprehensive source being Zhong Hua Ben Cao (Encyclopedia of Chinese Materia Medica), published in 1999.The Encyclopedia lists 23 species of Aristolochia, though with little mention of toxicity.