FZ volume:9 part:2 (1997) Aristolochiaceae by B.L. Stannard
A family of about 12 genera and 450–500 species, mainly in the tropics and subtropics but some in the warm temperate regions.The genus Pararistolochia occurs in the F.T.E.A. area, but apparently not in the Flora Zambesiaca region.
Perennial herbs or shrubs, erect, scrambling or climbing, sometimes lianes, often with tuberous rhizomes.Leaves alternate, petiolate, exstipulate, simple, entire, sometimes lobed.Flowers terminal, axillary or borne on the stem (cauligerous), solitary, fasciculate or in few to many-flowered racemose or cymose inflorescences, hermaphrodite, epigynous, actinomorphic or zygomorphic, with or without bracts.Calyx petaloid, usually enlarged, basally tubular, expanding into a limb above; limb symmetrically 3-lobed, or unilateral and entire or lobed.Petals absent except in Saruma, vestigial in Asarum.Stamens 6–many in 1–2 or more whorls, free or adnate to the stylar column forming agynostemium; anthers 2-thecous with 4 pollen sacs, extrorse, dehiscing longitudinally.Ovary inferior, rarely half inferior, 4–6 locular, syncarpous or apocarpous in Saruma, placentas parietal or seemingly axile; ovules numerous, anatropous, in 1–2 vertical series in each locule, horizontal or pendulous; styles connate into a column; stigma 3–many-lobed.Fruit a capsule, dehiscing septicidally or irregularly, or more rarely indehiscent.Seeds usually many, variously shaped, raphe sometimes thickened and winged; endosperm abundant, embryo minute.