Harvard Pap. Bot. 11: 259. 2007.
Perennials; usually short-lived; apomictic; caudex not woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4.5 dm, glabrous throughout. Basal leaves: blade oblanceolate, 1.5–6 mm wide, margins entire, ciliate at petiole base, trichomes to 0.8 mm, surfaces sparsely pubescent, trichomes sessile, malpighiaceous (usually at margin) and 3- or 4-rayed, 0.15–0.4 mm. Cauline leaves: 5–17, often concealing stem proximally; blade auricles 1–3 mm, surfaces of distalmost leaves glabrous. Racemes 10–25-flowered, unbranched. Fruiting pedicels erect, straight, 5–10 mm, glabrous. Flowers erect at anthesis; sepals glabrous; petals purple, 6–9 × 1.5–2.5 mm, glabrous; pollen spheroid. Fruits erect, appressed to rachis, not secund, straight, edges parallel, 3.5–6.5 cm × 1.8–2.5 mm; valves glabrous; ovules 64–134 per ovary; style 0–0.2 mm. Seeds biseriate to sub-biseriate, 1.8–2.2 × 1–1.8 mm; wing continuous, 0.2–0.5 mm wide.
Phenology: Flowering Jun–Aug.
Habitat: Exposed rocky ridges, meadows, open forests near timberline
Elevation: 1500-3500 m
Alta., B.C., N.W.T., Yukon, Calif., Idaho, Mont., Oreg., Wash., Wyo.
Morphological evidence suggests that Boechera calderi is an apomictic species that arose through hybridization between B. lyallii and B. stricta (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison).