92. Boechera saximontana (Rollins) Windham & Al-Shehbaz, Harvard Pap. Bot. 12: 248. 2007; Arabis microphylla Nuttall var. saximontana Rollins, Rhodora 43: 429. 1941; Arabis williamsii Rollins var. saximontana (Rollins) Rollins, Amer. J. Bot. 70: 627. 1983 (same new combination was superfluously published in Cruciferae Continental North America 209. 1993); A. pendulocarpa A. Nelson var. saximontana (Rollins) Dorn, Vasc. Pl. Wyoming 295. 1988; Boechera williamsii (Rollins) Dorn var. saximontana (Rollins) Dorn, Vasc. Pl. Wyoming, ed. 3, 376. 2001. TYPE: United States, Wyoming, Big Horn Co., granitic hillside, Porcupine Creek, near Medicine Mountain, R92W, T56N, 8,500 ft, 6 Jul 1936, Louis O. Williams & Rua Williams 3264 (lectotype (plants with pubescent stems) designated by Windham & Al-Shehbaz (2007: 248), GH!; isolectoypes, MO!, 3RM!).
Plants short-lived perennials, with mostly non-woody caudices, lacking crowded, persistent leaf bases; apomictic, with spheroid pollen. Stems usually 1 per caudex branch, arising near ground surface from center of basal rosettes, 0.7–3.0 dm, lower parts with many short-stalked, 2–6-rayed trichomes 0.06–0.25 mm, upper parts glabrous. Leaves at stem bases narrowly oblanceolate, 1–3 mm wide, entire, ciliate near petiole bases with simple and spurred trichomes to 0.4 mm, blade surfaces sparsely to densely pubescent with short-stalked, 4–8-rayed trichomes 0.04–0.15 mm; cauline leaves 5–9, rarely concealing stem proximally, the uppermost glabrous, with auricles to 0.3–1 mm. Inflorescences mostly unbranched, 5–13-flowered; fruiting pedicels 3–8 mm, divaricate-ascending, straight, glabrous. Flowers ascending at anthesis; sepals pubescent; petals lavender, 4–5 ´ 0.5–0.8 mm, glabrous; ovules 78–112 per fruit. Fruits (2.5–)3.0–4.7 cm ´ 1.2–1.7 mm, divaricate-ascending, not appressed to rachises, not secund, straight, with parallel edges, glabrous; style 0.1–0.5 mm. Seeds uniseriate to subbiseriate, 1.1–1.4 ´ 0.7–0.9 mm; wing continuous, 0.05–0.12 mm wide.
Habitat: rocky soil in sagebrush and open conifer forest.
Elevation: 2400–2900 m.
Distribution: United States (Idaho, Wyoming).
Reproductive mode: apomictic triploid.