98. Boechera sparsiflora (Nuttall) Dorn, Vasc. Pl. Wyoming ed. 3, 376. 2002; Arabis sparsiflora Nuttall in Torrey & A. Gray, Fl. N. Amer. 1: 81. 1838; TYPE: United States, “Forest of the Rocky Mountains, towards the source of the Oregon,” T. Nuttall s.n. (holotype, BM!; isotype, PH!).
Arabis arcoidea A. Nelson, Bot. Gaz. 53: 220. 1912. TYPE: United States, Idaho, Canyon [Payette] County, New Plymouth, 2200 ft., 21 May 1910, J. F. Macbride 87 (holotype, RM!; isotypes, E!, GH!, 2MO!, RM!).
Arabis campyloloba Greene, Pittonia 4: 192. 1900. TYPE: United States, California, Siskiyou Co., near Yreka, May 1876, E. L. Greene 695 (Lectotype designated by Windham & Al-Shehbaz (2006: 83), NDG 5758, fruiting plant to the left).
Arabis peramoena Greene, Repert. Sp. Nov. Regni Veg. 5: 242. 1908; A. sparsiflora var. peramoena (Greene) Rollins, Res. Stud. State Coll. Wash. 4: 25. 1936. TYPE: United States, Oregon, Malheur Co., dry sandy soil of Willow Creek, 4 May 1900, W. C. Cusick 2369 (holotype, US!; isotypes, E!, GH!, MO!, NDG!, NY!, ORE!, POM!, RM!, WS!).
Arabis polytricha Greene, Leafl. Bot. Observ. Crit.2: 72. 1910. TYPE: United States,n California, Siskiyou Co., dry hill near Yreka, 8 May 1909, G. D. Butler 723 (holotype, NDG!; isotypes, DS!, NDG!, POM!, UC!).
Plants short-lived perennial to biennials, with or without caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per caudex branch, arising near ground surface from center of basal rosettes, 3–8 dm, lower parts with abundant simple and fewer short-stalked, 2-rayed trichomes 0.4–1.5 mm, upper parts glabrous or sparsely pubescent. Leaves at stem bases oblanceolate or linear-oblanceolate, 3–12 mm wide, entire or rarely dentate, ciliate proximally with mostly simple trichomes to 1 mm, blade surfaces densely pubescent with short-stalked, 2–5-rayed trichomes 0.3–0.8 mm; cauline leaves (9–)15–35, often concealing stem proximally, the uppermost glabrous or ciliate, with auricles 3–10 mm. Inflorescences mostly unbranched, 12–50-flowered; fruiting pedicels 3–10(–18) mm, ascending or rarely almost horizontal, straight or slightly recurved, with spreading, mostly simple trichomes or rarely glabrous. Flowers ascending at anthesis; sepals sparsely pubescent; petals lavender to purple or rarely white, 7–13 ´ 2–5 mm, glabrous; ovules 90–170 per fruit. Fruits 5–13 cm ´ 1.7–2.0 mm, ascending or rarely almost horizontal, not appressed to rachises, not secund, usually curved, with parallel edges, glabrous; style 0.05–0.30 mm. Seeds uniseriate, 1.5–2.0 ´ 1.0–1.5 mm; wing continuous, 0.1–0.2 mm wide. 2n = 14.
Habitat: rocky slopes, clay hills, and sandy soil in sagebrush and mountain shrub communities, meadows, and open conifer forests.
Elevation: 450–2750 m.
Distribution: Canada (British Columbia), United States (California, Idaho, Nevada, Oregon, Utah, Washington).
Reproductive mode: sexual diploid.