Annual or perennial herbs, producing milky sap. Leaves alternate, opposite or verticillate, toothed or rarely entire. Flowers axillary and solitary or in raceme-like inflorescences or cymes, bisexual and protogynous; bracteoles conspicuous and leaf-like at base of pedicel, or minute, or absent. Hypanthium usually oblique; calyx-lobes erect, spreading or deflexed; corolla slightly to distinctly zygomorphic, sometimes 2-lipped, lobes subequal or the upper 2 slightly narrower and/or longer, tube deeply slit to near the base on the upper side; staminal filaments free from corolla-tube or adnate at very base, anthers connate in a tube, all densely penicillate at tip; ovary 2-locular, stigma 2-lobed, the lobes linear and becoming revolute-recoiled, pollen-presenting hairs located on the style slightly below the stigma cleft. Fruit a capsule; seeds numerous, reticulate, ridged, or smooth.
About 20 species, mainly South African with 3 species in tropical Africa; 1 species naturalised in Australia.
KEY TO GENUS