Boechera paupercula |
Boechera serotina |
|
---|---|---|
boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress |
|
|
Habit | Perennials; long-lived; (cespitose); sexual; caudex often woody. | Biennials; short-lived; sexual; caudex not evident. |
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 plant, arising from center of rosette near ground surface, 4–10 dm, glabrous throughout. |
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 obovate to oblanceolate, 5–20 mm wide, margins dentate, not ciliate, surfaces glabrous or subapically puberulent, trichomes simple, 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. |
30–80, not concealing stem; blade auricles absent, surfaces of distalmost leaves glabrous. |
Racemes | 3–8-flowered, unbranched. |
70–150-flowered, multi-branched. |
Flowers | erect at anthesis; sepals glabrous or sparsely pubescent; petals lavender to purplish, 4–6(–7) × 1–2 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals glabrous; petals white, 2.8–4 × 0.6–1 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
divaricate-ascending to horizontal, straight or gently recurved, 6–15 mm, glabrous. |
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. |
divaricate-ascending to widely pendent, not appressed to rachis, not secund, straight or slightly curved, edges parallel, 4.3–7.9 cm × 1.5–1.8 mm; valves glabrous; ovules 30–42 per ovary; style 0.1–0.2 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 × 0.7–1 mm; wing continuous or, sometimes, distal (rarely absent), 0.1–0.2 mm wide. |
Flowering | Jul–Sep. |
|
Shale | barrens and wooded slopes of crumbling shale; of conservation concern; 100–500 m; Va., W.Va. |
|
2n | = 14. |
|
Boechera paupercula |
Boechera serotina |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Sep. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Shale barrens and wooded slopes of crumbling shale |
Elevation | 2400-3400 m (7900-11200 ft) | 100-500 m (300-1600 ft) |
Distribution |
CA; ID; OR; WA; WY
|
VA; WV |
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 serotina is unique among members of the genus in its highly branched inflorescences and late (summer–fall) anthesis. it is in the center for plant conservation’s national collection of endangered plants of conservation concern (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 405. |
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 serotina |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | (E. S. Steele) Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 249. (2007) |
Web links |
|