Family Sometimes included in Pedaliaceae.
Habit and leaf form. Glutinous-villous herbs. Annual, or perennial; often tuberous. Leaves alternate, or opposite; petiolate; non-sheathing; simple. Leaf blades dorsiventral; cross-venulate. Leaves without stipules. Leaf anatomy. Hairs present; glandular hairs present. Stem anatomy. Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes. The terminal inflorescence unit racemose. Inflorescences terminal; terminal racemes. Flowers pedicellate; very irregular; zygomorphic. The floral asymmetry involving the perianth and involving the androecium. Flowers 5 merous; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous (but sometimes nearly free, split down one side and spathaceous in Craneolaria); lobed; blunt-lobed; with the median member posterior. Corolla present; 5; 1 -whorled; gamopetalous; imbricate; unequal but not bilabiate, or bilabiate. Androecial members definite in number. Androecium 3, or 5. Androecial sequence not determinable. Androecial members adnate (epipetalous); markedly unequal; free of one another; 1 -whorled. Androecium including staminodes. Staminodes 1, or 3 (the posterior member always reduced); representing the posterior median member, or the posterior median member and the posterior-lateral pair. Stamens 2 (the shorter androecial members sometimes sterile, as well as the posterior one, in Martynia), or 4; didynamous, or not didynamous, not tetradynamous; reduced in number relative to the adjacent perianth; oppositisepalous; all alternating with the corolla members. Anthers connivent; dehiscing via longitudinal slits; tetrasporangiate. Gynoecium 2 carpelled. The pistil 1 celled, or 4 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary unilocular; 1 locular (but rendered more or less 4-locular in the fruit, by union of the T-shaped placentas with one another and with the endocarp). Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium median; stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1, or 2; when single, 2 - lobed. Placentation parietal. Ovules in the single cavity 3–100 (‘few to many’); anatropous.
Fruit and seed features. Fruit fleshy to non-fleshy; dehiscent; a capsule. Capsules loculicidal (the soft outer pericarp shed, the inner woody). Dispersal by animals, associated with usually hooked or curved spurs which develop from the tip of the midrib of each carpel. Seeds scantily endospermic. Cotyledons 2. Embryo straight. Seedling. Germination phanerocotylar.
Geography, cytology, number of species. Neotropical. World distribution: Tropical and subtropical South America, North ans central America and Mexico, Australasia. 13 species.