76. Boechera platysperma (A. Gray) Al-Shehbaz, Novon 13: 388. 2003; Arabis platysperma A. Gray, Proc. Amer. Acad. Arts 6: 519. 1865. TYPE: United States, California, Alpine Co., Ebbetts Pass, 1863, W. H. Brewer 1989 (lectotype designated by Rollins (1941: 473), GH!; isotypes, MO!, UC!, US!).
Arabis inamoena Greene, Repert. Sp. Nov. Regni Veg. 5: 243. 1908, not Greene, Leafl. Bot. Observ. Crit. 2: 158. 1911. TYPE: United States, California, Tulare Co., Long Meadow, 8000-9000 ft, 7-14 July 1888, D. Palmer 192 (holotype, US!; isotype, K!).
A. oligantha Greene, Repert. Sp. Nov. Regni Veg. 5: 243. 1908. TYPE: United States, California, Fresno Co., Dinkey Creek, 25 June-15 July 1900, 5300 ft, H. M. Hall & H. P. Chandler 354 (holotype, US!; isotypes, DS!, E!, K!, MO!, NY!, UC!).
Plants long-lived perennials, with woody caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per caudex branch, elevated above ground surface on woody bases or produced near ground surface, arising from center of basal rosettes, 0.6–2.8(–3.5) dm, lower parts with abundant short-stalked, 2–5-rayed trichomes 0.1–0.3 mm, upper parts glabrous or sparsely pubescent. Leaves at stem bases narrowly oblanceolate, 3–7(–10) mm wide, entire, ciliate near petiole bases with simple or spurred trichomes to 1 mm, blade surfaces densely pubescent with short-stalked, 2–5-rayed trichomes 0.1–0.3 mm; cauline leaves 3–7(–12), not concealing stem, the uppermost glabrous to sparsely pubescent, without auricles. Inflorescences unbranched, 2–7-flowered; fruiting pedicels 3–13 mm, ascending, straight, glabrous or with few appressed, branched trichomes. Flowers ascending at anthesis; sepals pubescent; petals creamy white to purplish, 4–6 ´ 1–2 mm, often with a few trichomes abaxially; ovules 16–44 per fruit. Fruits (2.5–)4.0–8.5 cm ´ 3.0–5.5 mm, ascending, not appressed to rachises, not secund, straight to slightly curved, with undulate (non-parallel) edges, glabrous; style 0.05–1.0 mm. Seeds uniseriate, 3–6(–8) ´ 2.0–3.5 mm; wing continuous, 0.8–2.5 mm wide. 2n = 14.
Habitat: rock outcrops and gravelly soil in dry pine forests and lodgepole-chaparral woodlands. Elevation: 1600–3000 m.
Distribution: United States (California, Oregon).
Reproductive mode: sexual diploid.