Boechera drepanoloba

Perennials; short- to long-lived; apomictic; caudex usually not woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4 dm, glabrous or sparsely pubescent proximally, trichomes sessile or subsessile, 2- or 3-rayed, 0.1–0.3 mm, glabrous distally. Basal leaves: blade oblanceolate, 2–6 mm wide, margins entire, ciliate along petiole, trichomes (submalpighiaceous or simple), to 0.6 mm, surfaces sparsely to densely pubescent, trichomes subsessile, 2–6-rayed, 0.1–0.3 mm. Cauline leaves: 3–15, often concealing stem proximally; blade auricles 0.7–2.5 mm, surfaces of distalmost leaves usually glabrous. Racemes 5–25-flowered, usually unbranched. Fruiting pedicels horizontal to ascending, straight or curved, 4–8 mm, glabrous. Flowers ascending at anthesis; sepals glabrous or pubescent with scattered trichomes; petals purple to lavender, 6–8 × 1.5–2.5 mm, glabrous; pollen spheroid. Fruits horizontal to ascending, secund, straight to slightly curved, edges parallel, 3–5.8 cm × 2–3.5 mm; valves glabrous; ovules 44–76(–104) per ovary; style 0.05–0.5 mm. Seeds uniseriate, 1.5–2.2 × 1.2–1.6 mm; wing continuous, 0.3–0.7 mm wide.

Phenology: Flowering Jul–Aug.
Habitat: Rocky slopes and talus in alpine and subalpine habitats
Elevation: 2000-3800 m

Alta., Alaska, Colo., Idaho, Mont., Oreg., Utah, Wash., Wyo.

Discussion

Morphological evidence suggests that Boechera drepanoloba is an apomictic species that arose through hybridization between B. lemmonii and B. stricta (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison).

Selected References

None.

Lower Taxa