42. Boechera harrisonii (S. L. Welsh) Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 266. 2007; Arabis harrisonii S. L. Welsh in S. L. Welsh et al., Utah Fl., ed. 3. 256. 2003; Boechera microphylla (Nuttall) Dorn var. harrisonii (S. L. Welsh) N. H. Holmgren, Brittonia 56: 246. 2004. TYPE: United States, Utah, Utah Co.: South Fork Provo Canyon, 2 miles [3.2 km] east of Vivian Park, 5300 m, 6 May 1950, B. F. Harrison 11474 [11747 in protologue] (holotype, BRY!; isotypes, BRY!, GH!).
Plants long-lived, somewhat cespitose perennials, often with woody caudices, lacking crowded, persistent leaf bases; apomictic, with spheroid pollen. Stems usually 3–7 per caudex branch, arising near ground surface from margin of basal rosettes, 0.5–2.5 dm, lower parts with few short-stalked, 2–3-rayed trichomes 0.06–0.2 mm or rarely glabrous, upper parts glabrous. Leaves at stem bases narrowly oblanceolate, 2–4 mm wide, entire or somewhat dentate, ciliate near petiole bases with simple trichomes to 0.5 mm, blade surfaces sparsely pubescent with short-stalked, 2–5-rayed trichomes 0.1–0.25 mm; cauline leaves 3–7, not concealing stem, the uppermost glabrous, with auricles 0.5–1.5 mm. Inflorescences mostly unbranched, 5–12-flowered; fruiting pedicels 8–12 mm, divaricate-ascending, straight, glabrous. Flowers ascending at anthesis; sepals pubescent; petals lavender, 5.0–7.5 ´ 0.8–1.5 mm, glabrous; ovules 64–86 per fruit. Fruits 3.0–4.7 cm ´ 1.0–1.5 mm, divaricate-ascending or (rarely) nearly horizontal, not appressed to rachises, not secund, curved to straight, with parallel edges, glabrous; style 0.2–0.5 mm. Seeds uniseriate, 1.1–1.3 ´ 0.8–1.1 mm; wing continuous but narrower at seed margin, 0.08– 0.1 mm wide.
Habitat: limestone and quartzite cliffs.
Elevation: 1500–1600 m.
Distribution: United States (Utah/Utah and Wasatch counties).
Reproductive mode: apomictic triploid.