68. Boechera paupercula (Greene) Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 75. 2006; Arabis paupercula Greene, Leafl. Bot. Observ. Crit. 2: 77. 1910. TYPE: United States, California, Tulare County, Farewell Gap, 10,600 ft, Sep 1897, C. A. Purpus 5229½ (holotype, US!; isotypes, E!, GH!, MO!, UC!).
Arabis nubigena J. F. Macbr. & Payson, Contr. Gray Herb. 49: 62. 1917; A. lyallii S. Wats. var. nubigena (J. F. Macbr. & Payson) Rollins, Rhodora 43: 367. 1941; A. microphylla Nuttall var. nubigena (J. F. Macbr. & Payson) Rollins, Res. Stud. State Coll. Wash. 4: 40. 1936. TYPE: United States, Idaho, Blaine County, gravelly flat, exposed alpine summit, Smoky Mts., 9000 ft, 13 Aug 1916, J. F. Macbride & E. B. Payson 3772 (holotype, GH!; isotypes, CAS!, E!, K!, MO!, NY!, POM!, RM!, US!).
Plants long-lived, cespitose perennials, often with woody 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, 0.3–1.5 dm, lower parts with abundant simple and short-stalked, 2–4-rayed trichomes (0.07)0.10–0.20 mm, upper parts glabrous or sparsely pubescent. Leaves at stem bases linear-oblanceolate, 1–3(–5) mm wide, entire, ciliate proximally with trichomes to 0.4 mm, blade surfaces densely pubescent with short-stalked, 2–6-rayed trichomes (0.07)0.10–0.20 mm; cauline leaves 2–6, rarely concealing stem, the uppermost glabrous, without auricles or (rarely) 0.2–1.5 mm. Inflorescences unbranched, 3–8-flowered; fruiting pedicels 3–9 mm, erect, straight, glabrous or sparsely pubescent. Flowers erect at anthesis; sepals glabrous or sparsely pubescent; petals lavender to purplish, 4–6(–7) ´ 1–2 mm, glabrous; ovules 24–40 per fruit. Fruits 2.5–5.5 cm ´ 1.3–1.7(–2.0) mm, erect, appressed to rachises, not secund, straight, with parallel edges, glabrous; style 0.2–1.0 mm. Seeds uniseriate or rarely subbiseriate, 1.5–2(–2.5) ´ 1.0–1.4 mm; wing continuous, 0.3–1.0 mm wide.
Habitat: rock outcrops, talus slopes, and gravelly soil in alpine and subalpine habitats.
Elevation: 2400–3350 m.
Distribution: United States (California, Idaho, Oregon, Washington, Wyoming).
Reproductive mode: sexual diploid.