Herbs or shrubs. Whole plant usually covered with ± stiff hairs seated on large tubercles. Leaves alternate, sometimes basal, rarely a few opposite; stipules absent. Flowers usually in terminal or axillary cymes, which may be coiled in the bud and unrolling to resemble a one-sided raceme or spike. Flowers bisexual, regular or irregular. Sepals 5, free or basally connate, persistent. Corolla tubular or rotate, 5-lobed. Stamens 5, epipetalous, alternating with the corolla lobes. Ovary superior, 2-carpellary, 2-locular but becoming 4-locular at maturity; Style simple, terminal or gynobasic. Fruit schizocarpic, splitting into four 1-seeded articles or 2 mericarps, usually with a rugose spiny or sometimes glabrous epicarp; rarely the articles ± drupaceous. 156 gen., widespread, temp. to trop.