7. Boechera calderi (G. A. Mulligan) Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 259. 2007; Arabis calderi G. A. Mulligan, Rhodora 97: 144. 1996. TYPE: Canada, British Columbia. Indian River at Mile 34 from Alaska Highway on Atlin road, common on open grassy flats on bench above river, ca. 59˚54' N, 133˚48' W, 9 Jun 1960, J. A. Calder & J. M. Gillett 25180 (holotype, DAO!).
Plants mostly short-lived perennials, with non-woody caudices, lacking crowded, persistent leaf bases; apomictic, with spheroid pollen. Stems usually 1 per caudex branch, arising near ground surface from center of basal rosettes, 1.0–4.5 dm, glabrous throughout. Leaves at stem bases oblanceolate, 1.5–6.0 mm wide, entire, ciliate at petiole base with trichomes to 0.8 mm, blade surfaces sparsely pubescent with sessile, malpighiaceous (mostly at margin) and 3–4-rayed trichomes 0.15–0.40 mm; cauline leaves 5–17, often concealing stem proximally, the uppermost glabrous, with auricles 1–3 mm. Inflorescences unbranched, 10–25-flowered; fruiting pedicels
5–10 mm, erect, straight, glabrous. Flowers erect at anthesis; sepals glabrous; petals purple, 6–9 ´ 1.5–2.5 mm, glabrous; ovules 64–134 per fruit. Fruits 3.5–6.5 cm ´ 1.8–2.5 mm, erect, appressed to rachis, not secund, straight, with parallel edges, glabrous; style obsolete or to 0.2 mm. Seeds biseriate to subbiseriate, 1.8–2.2 ´ 1–1.8 mm; wing continuous, 0.2–0.5 mm wide.
Habitat: exposed rocky ridges, meadows, and open forests near timberline.
Elevation: 1500–3500 m.
Distribution: Canada (Alberta, British Columbia, Northwest Territories, Yukon), United States (California, Idaho, Montana, Oregon, Washington, Wyoming).
Reproductive mode: apomictic triploid.