Boechera paupercula
Harvard Pap. Bot. 11: 75. 2006.
Perennials; long-lived; (cespitose); sexual; caudex often woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.5 dm, densely pubescent proximally, trichomes simple and short-stalked, 2–4-rayed, (0.07–)0.1–0.2 mm, glabrous or sparsely pubescent distally. Basal leaves: blade linear-oblanceolate, 1–3(–5) mm wide, margins entire, ciliate proximally, trichomes to 0.4 mm, surfaces densely pubescent, trichomes short-stalked, 2–6-rayed, (0.07–)0.1–0.2 mm. Cauline leaves: 2–6, rarely concealing stem; blade auricles 0 (or 0.2–1.5) mm, surfaces of distalmost leaves glabrous. Racemes 3–8-flowered, unbranched. Fruiting pedicels erect, straight, 3–9 mm, glabrous or sparsely pubescent. Flowers erect at anthesis; sepals glabrous or sparsely pubescent; petals lavender to purplish, 4–6(–7) × 1–2 mm, glabrous; pollen ellipsoid. Fruits erect, appressed to rachis, not secund, straight, edges parallel, 2.5–5.5 cm × 1.3–1.7(–2) mm; valves glabrous; ovules 24–40 per ovary; style 0.2–1 mm. Seeds usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide.
Phenology: Flowering Jun–Aug.
Habitat: Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats
Elevation: 2400-3400 m
Distribution
Calif., Idaho, Oreg., Wash., Wyo.
Discussion
Boechera paupercula is usually subsumed under Arabis (Boechera) lyallii but is amply distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison).
Selected References
None.