Pterodiscus

Perennial herbs, with a persistent basal organ consisting either of a short, swollen aerial stem arising from a subterranean tuber of +/- the same diameter, or a woody, not distinctly swollen stem (rarely stems) arising from a napiform or pyriform subterranean tuber; several annual shoots, usually unbranched, arise from top of basal organ. Leaves opposite or alternate, linear to broadly oblong, entire, undulate, dentate, pinnatifid or pinnatipartite, subsucculent, sometimes glandular beneath. Flowers solitary, axillary, shortly pedicellate; yellow, orange, red or purple, sometimes mixed on one flower. Calyx small, persistent, much shorter than corolla tube; segments sometimes unequal. Corolla +/- 2-lipped; tube funnel-shaped, or narrowly cylindrical and constricted in lower part, often oblique or slightly gibbous at base (reduced spur); limb spreading, lobes subequal or clearly unequal, circular to oblate. Stamens didynamous, included; filaments linear, glandular-villous at base; anthers with thecae divergent, apiculate; staminodes 0(1). Nectary somewhat inconspicuous. Ovary 2-locular; locules undivided; ovules 1-3 or 5 or 6 per locule, pendulous; style linear, included; stigma of 2 ovate lobes, with fimbriate margins. Fruit indehiscent, laterally compressed, with a longitudinal parchment-like wing on each of 4 edges, unarmed, +/- circular or ovate in lateral view, often asymmetrical, apex emarginate or apiculate, base usually emarginate; upper part of fruit sterile and forming a distinct beak; mesocarp spongy with large cavities; endocarp thin, sclerified and very tough. Seeds 1 or 2 in each locule, variable in shape and testa structure.