Novon 13: 384. 2003
Perennials; long-lived; sexual; caudex woody. Stems usually 1 per caudex branch, arising from center of rosette, elevated above ground surface on woody base, 1.2–3 dm, glabrous throughout. Basal leaves: blade narrowly oblanceolate, 1.5–4 mm wide, margins entire, ciliate, trichomes (simple, mixed with fewer stalked, 2-rayed), 0.3–0.8 mm, surfaces glabrous. Cauline leaves: 6–12, not concealing stem; blade auricles absent, surfaces of distalmost leaves glabrous. Racemes 5–15-flowered, unbranched. Fruiting pedicels arched, strongly recurved proximally, 4–12 mm, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous; petals creamy white, 6–8 × 1.5–2 mm, glabrous; pollen ellipsoid. Fruits pendent, not appressed to rachis, usually secund, straight or slightly curved, edges often somewhat undulate (not parallel), 4–7.5 cm × 3–3.5 mm; valves glabrous; ovules 18–28 per ovary; style 2.5–5 mm. Seeds uniseriate, 3–4 × 2.5–3 mm; wing continuous, 0.5–1 mm wide. 2n = 14.
Phenology: Flowering May.
Habitat: Steep ridges, serpentine slopes
Elevation: 1200-1900 m
Boechera constancei was originally treated as a variety of Arabis (Boechera) suffrutescens; it is easily separated from that species by its non-auriculate cauline leaf blades, longer (6–8 versus 4.5–6 mm) petals that are creamy white (versus purple or rose-tipped), much longer style (2.5–5 versus 0.4–1.2 mm), and exerted anthers. This distinctive sexual diploid is thus far known only from the west slope of the Sierra Nevada in Plumas County.