55. Boechera lignifera (A. Nelson) W. A. Weber, Phytologia 51: 370. 1982; Arabis lignifera A. Nelson, Bull. Torrey Bot. Club 26: 123. 1899. TYPE: United States, Wyoming: Greene River, 14 Jun 1898, A. Nelson 4711 (Lectotype designated by Windham & Al-Shehbaz (2006: 7!), RM! 12591 [plant on right side of sheet]; isolectotypes, MO! [right-hand plant only], NY! [right-hand plant only], US!).
Plants short- to long-lived perennials, with mostly woody caudices, lacking crowded, persistent leaf bases; apomictic (with spheroid pollen) or sexual (with ellipsoid pollen). Stems usually 2–5 per caudex branch, often elevated on woody bases, arising laterally below sterile shoot, 1.2–4.0(–5.0) dm, lower parts with many short-stalked, 4–7-rayed trichomes 0.1–0.3 mm, upper parts sparsely pubescent to glabrous. Leaves at stem bases narrowly oblanceolate, 2–5(–8) mm wide, entire, rarely ciliate near petiole bases with simple or spurred trichomes to 1 mm, blade surfaces densely pubescent with short-stalked, 3–7-rayed trichomes 0.05–0.3 mm; cauline leaves 4–12(–17), rarely concealing stem proximally, uppermost leaves sparsely pubescent, with auricles 0.5–2 mm. Inflorescences mostly unbranched, 6–15(–25)-flowered; fruiting pedicels 5–16 mm, slightly descending, gently recurved, glabrous or with few appressed, branched trichomes. Flowers divaricate-ascending at anthesis; sepals pubescent; petals whitish but often aging pale lavender, 5–7 ´ 1.0–1.5 mm, glabrous; ovules 48–74 per fruit. Fruits 2.5–5.6 cm ´ 1.2–2.0 mm, widely pendent, not appressed to rachises, not secund, usually curved, with parallel edges, glabrous; style 0.1–0.2 mm. Seeds uniseriate, 1.0–1.3 ´ 0.8–1.0 mm; wing often continuous, 0.10–0.15 mm wide. 2n = 14.
Habitat: rocky slopes and sandy soil in sagebrush and pinyon-juniper woodland.
Elevations: 1700–2300 m.
Distribution: United States (Arizona, Colorado, Idaho, New Mexico, Utah, Wyoming).
Reproductive mode: sexual diploid.