33. Boechera formosa (Greene) Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 68. 2006; Arabis formosa Greene, Pittonia 4: 198. 1900. TYPE: United States, New Mexico, San Juan County, hills about Aztec, 5500 ft, 28 Apr 1899, C. F. Baker 345 (holotype, NDG!; isotypes, E!, GH!, K!, MO!, 2NDG!, NY!, 2RM!, RSA!, UC!, US!).
Arabis pulchra M. E. Jones ex S. Watson var. pallens M. E. Jones, Contr. W. Bot. 14: 42. 1912; Boechera pulchra (M. E. Jones ex S. Watson) W. A. Weber subsp. pallens (M. E. Jones) W. A. Weber, Phytologia 51: 371. 1982. B. pulchra var. pallens (M. E. Jones) Dorn, Vasc. Pl. Wyoming, ed. 3. 376. 2001. TYPE: United States, Colorado, Mesa Co., Westwater, 6 May 1891, M. E. Jones s.n. (lectotype, designated by Rollins (1941: 460), POM!; isolectotypes, GH!, MO!, NY!, ORE!, US!).
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, arising from center of leaf tuft, 2.0–5.5 dm, lower parts with abundant, short-stalked, 4–7-rayed trichomes 0.1–0.4 mm, upper parts similarly pubescent. Leaves at stem bases linear to linear-oblanceolate, 2–3(–4) mm wide, entire, occasionally ciliate near petiole base with simple or 2-rayed trichomes to 0.8 mm, blade surfaces densely pubescent with short-stalked, 4–8-rayed trichomes 0.1–0.3 mm; cauline leaves 7–18, concealing stem proximally, the uppermost densely pubescent, lacking auricles. Inflorescences mostly unbranched, 6–26-flowered; fruiting pedicels 5–10(–20) mm, horizontal to descending, usually recurved, with appressed, branched trichomes. Flowers divaricate at anthesis; sepals pubescent; petals white to pale lavender, 8–18 ´ 2.5–4.4(–5.5) mm, glabrous; ovules 72–98 per fruit. Fruits 4.3–7.0 cm ´ 1.6–3.0 mm, divaricate-descending to reflexed, usually not appressed to rachises, rarely somewhat secund, straight, with parallel edges, pubescent throughout; style ca. 0.1 mm. Seeds biseriate, 1.2–1.6 ´ 1.0–1.2 mm; wing continuous, 0.1–0.2 mm wide. 2n = 14.
Habitat: rocky slopes and sandy soil in blackbrush, sagebrush, and pinyon-juniper communities.
Elevation: 1300–1900 m.
Distribution: United States (Arizona, Colorado, New Mexico, Utah, Wyoming).
Reproductive mode: sexual diploid