2174.000 Aristolochia L.

Perennial herbs or woody climbers. Flowers zygomorphic. Perianth (calyx) zygomorphic; the base swollen, the upper part narrower, ± cylindric (tube) with single, entire lobe (limb), rarely 0 or 3-lobed. Petals absent. Stamens usually 6, in one whorl, connate with the stylar column. Fruit a septicidal capsule.

Very clear diagrams of the structure of the perianth and an explanation of the terms utricle and syrinx are set out on page 117 of Pfeifer, H.W. (1966). Revision of the North and Central American Hexandrous species of Aristolochia (Aristolochiaceae). Annals of the Missouri Botanical Garden 53(2): 115-196.

Derivation of name: from the Greek aristos meaning excellent and locheia, childbirth, referring to the belief that certain species assisted with delivery.

Worldwide: 120 species, widely distributed in the tropics and subtropics; some in warm temperate regions.

Botswana: 1 taxon.