Plants 0.5-3(-5) × 0.5-3 dm. Leaf blades oblanceolate to narrowly elliptic, 1.5-3(-4) × 0.1-0.3(-0.5) cm, apex acute. Involucres distinctly and prominently ribbed at maturity. 2n = 38, 40, 42, (46). Flowering Feb-Jul. Sandy places, mixed grassland, saltbush, creosote bush, and sagebrush communities, pinyon-juniper woodlands; -60-3000 m; Ariz., Calif., Nev.; Mexico (Baja California, Sonora). Variety brevicornu is known only from the warm Mojave and Sonoran deserts.