60. Boechera missouriensis (Greene) Al-Shehbaz, Novon 13: 387. 2003; Arabis missouriensis Greene, Repert. Sp. Nov. Regni Veg. 5: 244. 1908; A. laevigata var. missouriensis (Greene) Ahles, J. Elisha Mitchell Sci. Soc. 80: 172. 1964. TYPE: United States, Missouri, Montier, 15 May 1894, B. F. Bush 31 (holotype, NDG!; isotype, GH!).
Arabis viridis var. deamii M. Hopkins, Rhodora 39: 157. 1937; A. missouriensis var. deamii (M. Hopkins) M. Hopkins, Rhodora 45: 269. 1943. TYPE: United States, Indiana, Lagrange Co., 5 miles E of Lagrange, on cleared gravelly slope on E side of old tamarack bog, 4 Jun 1922, D. C. Deam 36370 (holotype, GH!).
A. viridis Harger Rhodora 13: 38. 1911. TYPE: United States, Connecticut, Southbury, dry crevices of trap cliff, 25 Jul 1908, E. B. Harger 5322 (lectotype designated by Hopkins (1937: 157), GH!).
Plants biennials, without evident caudices, lacking crowded, persistent leaf bases; sexual, with ellipsoid pollen. Stems usually 1 per plant, arising near ground level from center of basal rosettes, 2.0–7.5 dm, lower parts with few simple trichomes to 0.5 mm, or glabrous throughout. Leaves at stem bases oblanceolate, 5–18 mm wide, lyrate-pinnatifid, often minutely ciliate-mucronate on lobes, blade surfaces glabrous or sparsely pubescent with simple trichomes 0.1–0.5 mm; cauline leaves 10–45, often concealing stem proximally, glabrous with auricles 1–5 mm. Inflorescences occasionally branched, 18–47-flowered; fruiting pedicels 5–13 mm, suberect to divaricate-ascending, straight or slightly curved, glabrous. Flowers ascending at anthesis; sepals glabrous; petals white, 5–10 ´ 1.0–1.5 mm, glabrous; ovules 60–86 per fruit. Fruits 6–11 cm ´ 1.5–2.0 mm, ascending to divaricate-ascending, not appressed to rachises, not secund, curved, with parallel edges, glabrous; style 0.1–1.0 mm. Seeds uniseriate, 1.2–2.0 ´ 1.0–1.2 mm; wing continuous, 0.1–0.4 mm wide.
Habitat: rocky bluffs, wooded slopes, and valley bottoms.
Elevation: 50–300 m.
Distribution: United States (Arkansas, Connecticut, Georgia, Illinois, Kentucky, Massachusetts, Missouri, New York, North Carolina, Oklahoma, South Carolina, Wisconsin).
Reproductive mode: sexual diploid.