Boechera paupercula |
Boechera atrorubens |
|
---|---|---|
boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress |
black-flower rockcress, dark-red-flower rockcress, purple sickle-pod rock-cress, sicklepod rockcress |
|
Habit | Perennials; long-lived; (cespitose); sexual; caudex often woody. | Perennials; usually short-lived; sexual; caudex not 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. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 0.8–6 dm, sparsely pubescent proximally, trichomes short-stalked and simple, (scattered), 2-rayed, 0.1–0.15 mm, glabrous 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. |
blade oblanceolate, 4–10 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 3- or 4-rayed, 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. |
7–25, concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves glabrous. |
Racemes | 3–8-flowered, unbranched. |
6–20-flowered, usually unbranched. |
Flowers | erect at anthesis; sepals glabrous or sparsely pubescent; petals lavender to purplish, 4–6(–7) × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals dark reddish purple (drying indigo), 7–9 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
ascending, usually straight, 5–10 mm, glabrous or pubescent, trichomes spreading, simple. |
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. |
ascending, not appressed to rachis, not secund, curved or straight, edges parallel, (4–)6–12 cm × 1.7–2.2 mm; valves glabrous; ovules 80–100 per ovary; style 0.2–0.5 mm. |
Seeds | usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide. |
uniseriate, 1.2–1.7 × 0.9–1.2 mm; wing lateral and distal, 0.1–0.2 mm wide. |
Boechera paupercula |
Boechera atrorubens |
|
Phenology | Flowering Jun–Aug. | Flowering Apr–May. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Rocky summits and sandy loam on sagebrush slopes |
Elevation | 2400-3400 m (7900-11200 ft) | ca. 600 m (ca. 2000 ft) |
Distribution |
CA; ID; OR; WA; WY
|
OR; WA
|
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). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera atrorubens is often treated as a variety of B. sparsiflora (e.g., R. C. Rollins 1993), it is readily separated from that species by having proximal stems sparsely (versus densely) pubescent with much smaller (0.15 versus 1.5 mm) trichomes. The two taxa rarely grow in proximity and, in areas where they are sympatric, B. atrorubens is further distinguished by its narrower (1.5–2 versus 2–5 mm) petals that are dark reddish purple to indigo (versus lavender or white). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 366. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis paupercula, Arabis lyallii var. nubigena, Arabis microphylla var. nubigena, Arabis nubigena | Arabis atrorubens, Arabis atriflora, Arabis sparsiflora var. atrorubens |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | (Suksdorf ex Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 64. (2006) |
Web links |
|
|