11. Boechera cobrensis (M. E. Jones) Dorn, Vasc. Pl. Wyoming, ed. 3. 375. 200; Arabis cobrensis M. E. Jones, Contr. W. Bot. 12: 1. 1908. TYPE: United States, Nevada, Elko Co., Cobre, clay hills, 6000 ft., 16 Jun 1906, M. E. Jones s.n. (holotype, POM!; isotypes, BM!, CAS!, MO!, OSC!, POM!, UC!, US!).
Arabis canescens Nuttall in Torrey & A. Gray, Fl. N. Amer. 1: 83. 1838, not Brocchi. Bibliot. Ital. 29: 90. 1823. TYPE: United States, Rocky Mountains, T. Nuttall s.n. (holotype, BM!; isotypes, GH!, K!, NY!, PH!).
Plants long-lived, often cespitose perennials, with somewhat woody caudices, usually lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per caudex branch, arising near ground level from center of basal rosettes, (1.2–)2.5–6.0 dm, lower parts with abundant, short-stalked, 4–10-rayed trichomes 0.1–0.2 mm, upper parts sparsely pubescent to glabrous. Leaves at stem bases linear to narrowly oblanceolate, 1–4 mm wide, entire, ciliate near petiole bases with simple trichomes to 0.6 mm, blade surfaces densely pubescent with short-stalked, 4–10-rayed trichomes 0.1–0.2 mm; cauline leaves 5–10, not concealing stem, the uppermost usually sparsely pubescent, with auricles 1.0–1.5 mm. Inflorescences often sparingly branched, 10–25-flowered; fruiting pedicels 4–17 mm, divaricate-ascending to horizontal, often straight proximally, usually strongly recurved or reflexed distally, with appressed, branched trichomes or rarely glabrous. Flowers divaricate-ascending at anthesis; sepals pubescent; petals white to lavender, 3.5–6.0 ´ 0.7–1.0 mm, glabrous; ovules 34–64 per fruit. Fruits 2.5–5.5 cm ´ 1.7–2.5 mm, pendent, not appressed to rachises, not secund, straight or slightly curved, with parallel edges, glabrous; style 0.05–0.20 mm. Seeds uniseriate, 1.4–1.8 ´ 1.0–1.2 mm; wing continuous, 0.25–0.50 mm wide. 2n = 14.
Habitat: sandy soil, usually under shelter of shrubs in semi-desert communities.
Elevation: 1200–2800 m.
Distribution: United States (California, Idaho, Nevada, Oregon, Wyoming).
Reproductive mode: sexual diploid.