Herbs, perennial; roots cylindric, cordlike. Stems ascending, openly forked, sparsely leafy, leaves ± evenly distributed. Leaves sessile or subsessile, ± equal proximal to inflorescence, margins entire. Inflorescences axillary and terminal in open, few-branched cymes; involucres not or only slightly accrescent, widely bell-shaped, with 1-3 flowers inserted at base. Flowers: perianth funnelform, gradually expanded from narrow tube; stamens 5. Fruits with 5 low, prominent ribs or blunt angles, narrowly obovate, base prominently constricted, apex nipplelike, surface of fruit smooth or tuberculate, spreading-puberulent, mucilaginous when wetted.

Species 1: sw United States, n Mexico.