94. Boechera serotina (Steele) Windham & Al-Shehbaz, Harvard Pap. Bot. 12: 249. 2007; Arabis serotina Steele, Contr. U.S. Natl. Herb. 13: 365. 1911. TYPE: United States, Virginia, Bath County, Alleghany Mts., vicinity of Millboro, disintegrating shale, 500 m, 21 Aug 1907, Edward S. Steele s.n. (holotype, US!).
Plants biennials, without evident caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per plant, arising near ground surface from center of basal rosettes, 4–10 dm, glabrous throughout. Leaves at stem bases obovate to oblanceolate, 5–20 mm wide, dentate, not ciliate, blade surfaces glabrous or subapically puberulent with simple trichomes 0.1–0.2 mm; cauline leaves 30–80, not concealing stem, the uppermost glabrous, without auricles. Inflorescences highly branched, 70–150-flowered; fruiting pedicels 6–15 mm, divaricate-ascending to horizontal, straight or gently recurved, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous; petals white, 2.8–4.0 ´ 0.6–1.0 mm, glabrous; ovules 30–42 per fruit. Fruits 4.3–7.9 cm ´ 1.5–1.8 mm, divaricate-ascending to widely pendent, not appressed to rachises, not secund, straight or slightly curved, with parallel edges, glabrous; style 0.1–0.2 mm. Seeds uniseriate, 1.2–1.7 ´ 0.7–1.0 mm; wing continuous or sometimes distal, 0.1–0.2 mm wide, rarely absent. 2n = 14.
Habitat: shale barrens and wooded slopes of crumbling shale.
Elevation: 100–500 m.
Distribution: United States (Virginia, West Virginia).
Reproductive mode: sexual diploid.