Perennials; caudex simple, (usually woody); densely pubescent, trichomes (sessile or short-stalked), several-rayed, rays simple or furcate, (smooth or tuberculate). Stems simple from base, erect, (unbranched, sparsely leaved), to 7 dm. Basal leaves: blade elliptic or obovate to oblong, 4-15 cm, margins entire, dentate, or lyrate-pinnatifid. Cauline leaves: (proximal often narrowed to short petiole, distal sessile); blade broadly elliptic to obovate or rhombic, 0.5-3(-5) cm, margins entire. Racemes dense or slightly elongated. Fruiting pedicels (spreading or recurved, loosely sigmoid), 5-25 mm. Flowers: sepals elliptic to ovate, 3.5-6(-7) mm, (median pair usually thickened apically, cucullate); petals (white, often purple-veined, fading purplish), suborbicular to obovate, obdeltate, or cuneate, 4.5-10(-12) mm, (often narrowed to broad claw, apex emarginate, less frequently claw undifferentiated from blade). Fruits (pendent or horizontal, sessile or substipitate), subglobose to broadly ellipsoid, not or slightly inflated, (4-)5-8 mm; valves (not retaining seeds after dehiscence), glabrous throughout; replum as wide as or wider than fruit; ovules 4-8(-12) per ovary; style 1-3(-4) mm. Seeds flattened. 2n = 18, 36. Flowering Mar-Oct. Rocky draws, canyons, stony hills, ridges, rock crevices on limestone ledges, lava cliffs, sand and gravel of dry stream beds, rocky slopes, talus, shade of bushes or cactus clumps; 400-2400 m; Ariz., N.Mex., Tex.; Mexico (Chihuahua, Coahuila, Sonora).