Arabis puberula Nuttall in J. Torrey and A. Gray, Fl. N. Amer. 1: 82. 1838; A. arida Greene; A. beckwithii S. Watson; A. lignipes A. Nelson var. impar A. Nelson; A. sabulosa M. E. Jones; A. subpinnatifida S. Watson var. beckwithii (S. Watson) Jepson; A. subpinnatifida var. impar (A. Nelson) Rollins; Boechera beckwithii (S. Watson) Dorn

Perennials; short-lived; sexual; caudex not woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, (1-)2-6.3 dm, densely pubescent proximally, trichomes short-stalked, 3-8-rayed, 0.1-0.3(-0.5) mm, similarly pubescent distally. Basal leaves: blade oblanceolate to linear-oblanceolate, 1.5-5 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5-12-rayed, 0.05-0.2 mm. Cauline leaves: 7-45(-65), concealing stem proximally; blade auricles absent or 0.7-3 mm, surfaces of distalmost leaves pubescent. Racemes 10-40(-64)-flowered, usually unbranched. Fruiting pedicels pendent, recurved distal to horizontal to ascending base, 4-10 mm, pubescent, trichomes appressed, branched. Flowers ascending to descending at anthesis; sepals pubescent; petals white to lavender, 5-9 × 0.8-1.8 mm, glabrous; pollen ellipsoid. Fruits closely pendent, rarely appressed to rachis, sometimes somewhat secund, usually straight, edges parallel, 3-6.5 cm × 1.9-2.2 mm; valves pubescent throughout; ovules 38-64 per ovary; style 0.05-0.1 mm. Seeds uniseriate, 1.4-1.8 × 1-1.4 mm; wing continuous, 0.1-0.3 mm wide. 2n = 14.

Flowering Apr-Jul. Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities; 1300-2900 m; Calif., Nev., Oreg., Utah.

Boechera puberula is a diploid species that appears to intergrade with both B. retrofracta and B. subpinnatifida. The glabrous-fruited specimens discussed by R. C. Rollins (1993) represent apomictic hybrids with other species, primarily B. pendulocarpa.