100. Boechera stricta (Graham) Al-Shehbaz, Novon 13: 389. 2003; Turritis stricta Graham, Edinburgh New Philos. J. 7: 350. 1829; Arabis drummondii A. Gray, Proc. Amer. Acad. Arts 6: 187. 1864, not A. stricta Hudson, Fl. Angl. 1: 292. 1777; B. drummondii (A. Gray) A. Löve & D. Löve, Bot. Not. 128: 513. 1975; Erysimum drummondii (A. Gray) Kuntze, Rev. Gen. Pl. 2: 933. 1891; T. drummondii (A. Gray) Lunell, Amer. Midl. Naturalist 5: 236. 1918. TYPE: United States, Rocky Mountains, grown from seeds, Drummond s.n. (holotype, K!).
Arabis albertina Greene, Pittonia 4: 196. 1900. TYPE: Canada, Alberta, Elbow River, Rocky Mts, Lat 49°40´, Jun-Jul 1897, J. Macoun 18101 (holotype, NDG!).
Arabis connexa Greene, Pittonia 4: 197. 1900; A. drummondii var. connexa (Greene) Fernald, Rhodora 5: 231. 1903. TYPE: United States, Colorado, Mineral Co., near Pagosa Peak, 10500 ft, Aug 1899, C. F. Baker 341 (holotype, NDG 7759!; isotypes, E!, K!, MO!, 3NDG!, NY!, RM!, US!).
Arabis oxyphylla Greene, Pittonia 4: 196. 1900; A. drummondii var. oxyphylla (Greene) M. Hopkins, Rhodora 39: 143. 1937. TYPE: United States, Colorado, Clear Creek Co., near Empire, 1875, E. L. Greene s.n. (lectotype designated by Rollins (1941: 371), NDG 5275!).
Arabis philonipha A. Nelson ex Rydberg, Fl. Colorado 164. 1906, TYPE: United States, Wyoming, Albany Co., Telephone Mines, 1 Aug 1900, A. Nelson 7913 (lectotype designated by Rollins (1941: 371), GH!; isotypes, K!, MO!, 2NY!, ORE!, POM!, RM!, US!).
Streptanthus angustifolius Nuttall in Torrey & A. Gray, Fl. N. Amer. 1: 76. 1838, not A. angustifolia Lamarck Encycl. 1: 220. 1783; Boechera angustifolia (Nuttall) Dorn. TYPE: United States, towards the sources of the Platte, T. Nuttall s.n. (holotype, BM!; isotypes, GH!, NY!, PH!).
Plants mostly short-lived perennials or biennials, with mostly non-woody caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1–4 per caudex branch, arising near ground surface from center of basal rosette or (rarely) laterally below sterile shoot, 1.5–8.0(–10.2) dm, lower parts glabrous or with few sessile, 2-rayed (rarely simple trichomes) 0.3–0.7 mm, upper parts glabrous. Leaves at stem bases oblanceolate, 1.5–8.0(–14.0) mm wide, entire or rarely dentate, ciliate with sessile, 2-rayed (rarely simple at petiole bases) trichomes, blade surfaces with sessile, 2-rayed (malpighiaceous) trichomes 0.3–0.7 mm or occasionally glabrous; cauline leaves 6–52, concealing stem proximally, the uppermost glabrous, with auricles 0.5–3.0 mm. Inflorescences mostly unbranched, 8–35(–80)-flowered; fruiting pedicels 5–18(–25) mm, erect, straight, glabrous. Flowers erect at anthesis; sepals glabrous; petals white, often aging pale lavender, (5–)7–11 ´ 1.5–2.7 mm, glabrous; ovules 110–216 per fruit. Fruits 4.0–9.0(–10.2) cm ´ 1.5–3.5 mm, erect, appressed to rachises, not secund, straight, with parallel edges, glabrous; style 0.05–0.30 mm. Seeds biseriate, 1.3–2.2 ´ 1.0–1.6 mm; wing distal and lateral, 0.3–0.8 mm wide. 2n = 14.
Habitat: rocky slopes and gravelly soil in sagebrush and mountain shrub communities, open conifer and hardwood forests, and alpine meadows.
Elevation: 750–3900 m.
Distribution: Canada (Alberta, British Columbia, Northwest Territories, Quebec, Saskatchewan, Yukon), United States (Alaska, Arizona, California, Colorado, Idaho, Iowa, Maine, Massachusetts, Montana, Nevada, New Hampshire, New Mexico, North Dakota, Ohio, Oregon, Rhode Island, Utah, Vermont, Washington, Wisconsin, Wyoming).
Reproductive mode: sexual diploid.