2. Boechera arcuata (Nuttall) Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 64. 2006; Streptanthus arcuatus Nuttall in Torrey & A. Gray, Fl. N. Amer. 1: 77. 1838; Arabis arcuata (Nuttall) A. Gray, Proc. Amer. Acad. Arts 6: 187. 1864, non Shuttelworth ex Godet, Fl. Jura 1: 38. 1852; A. holboellii Hornemann var. arcuata (Nuttall) Jepson, Man. Fl. Pl. Calif. 430. 1925; A. sparsiflora Nuttall var. arcuata (Nuttall) Rollins, Res. Stud. State Coll. Wash. 4: 26. 1936. TYPE: United States, California, Santa Barbara, T. Nuttall s.n. (holotype, BM!; isotypes, GH!, K!, PH!).
Arabis maxima Greene, Pittonia 4: 192. 1900. TYPE: United States, California, not designated.
Plants mostly long-lived perennials, with well-developed, often woody caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per caudex branch, elevated on woody bases or produced at ground surface, arising from center of basal rosettes, (2–)3–8 dm, lower parts with many short-stalked, 2-rayed and simple trichomes to 1 mm, upper parts pubescent. Leaves at stem bases linear to oblanceolate, 2–7(–12) mm wide, entire or rarely denticulate, ciliate along petiole with trichomes to 1.5 mm, blade surfaces densely pubescent with short-stalked, 2–5-rayed (rarely some simple) trichomes 0.4–0.8 mm; cauline leaves 10–30(–45), often concealing stem proximally, the uppermost pubescent, with auricles 2–5(–6) mm. Inflorescences mostly unbranched, 12–50(–70)-flowered; fruiting pedicels 8–22 mm, divaricate-ascending or rarely horizontal, gently recurved or straight, with subappressed 2–4-rayed trichomes. Flowers ascending at anthesis; sepals pubescent; petals purple, 9–14 ´ 2–4 mm, glabrous or with a few trichomes abaxially; ovules 90–250 per fruit. Fruits (6–)8–13 cm ´ 1.5–2.2 mm, divaricate-ascending or rarely horizontal, not appressed to rachises, not secund, usually curved, with parallel edges, glabrous or with a few scattered trichomes; style 0.01–0.50 mm. Seeds uniseriate or subbiseriate, 1.5–1.7 ´ 1.0–1.2 mm; wing continuous, 0.1–0.2 mm wide.
Habitat: rocky hillsides and cliffs in pine forests and chaparral.
Elevation: 300–1800 m.
Distribution: United States (California).
Reproductive mode: sexual diploid.