Plants prostrate, decumbent, or erect; trichomes with large tubercles throughout, ± flat across middle. Basal leaves: blade margins entire. Racemes not or somewhat secund, usually dense and compact, sometimes slightly elongated in fruit. Fruiting pedicels usually sigmoid. Petals usually yellow, sometimes cream-yellow, cream-white, or white. Fruits as wide as or longer than wide, apex rounded-acute; valves glabrous inside; septum complete; ovules 8-16 per ovary; style to 7 mm. Flowering May-Jun. Gravelly loam soils, rocky basaltic slopes, limestone outcrops, ridges and flats, canyon bottoms, open pinyon-juniper woodlands; 2000-2500 m; Ariz., Calif., Nev., Utah; Mexico (Baja California). Populations of subsp. latifolia with flowers cream-yellow, cream-white, or white are frequently encountered on the Kaibab Plateau of northern Arizona.