Annuals or shrubs, often with unpleasant smell, usually covered with simple articulate, often tangled, malpighian or bladder (vesicular) hairs. Stems green or greyish, villous when young and glabrescent. Leaves terete, spoon-like, often shortened or reduced to the scales, more or less gibbous at base. Bracts longer than bracteoles or of equal size. Flowers axillary, solitary. Segments 5, hyaline, ovate or triangular, with wing-like projections. Stamens 4-5, often appendiculate. Stigmas 2. Segments of fruiting perianth with wing-like projections. Fruit with membranous pericarp; seed with horizontal embryo.