Boechera paupercula |
Boechera shockleyi |
|
---|---|---|
boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress |
Shockley's Rock cress |
|
Habit | Perennials; long-lived; (cespitose); sexual; caudex often woody. | Perennials; usually short-lived; sexual; caudex not woody, (rarely with persistent, crowded leaf bases). |
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–)2–5 dm, densely pubescent proximally, trichomes short-stalked, 7–12-rayed, 0.1–0.2 mm, densely to 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. |
blade oblanceolate, 3–10 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 7–12-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. |
14–60, concealing stem for most of length; blade auricles 0.5–4 mm, surfaces of distalmost leaves densely pubescent. |
Racemes | 3–8-flowered, unbranched. |
20–70-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 lavender, 6–9 × 0.8–1.2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
divaricate-ascending, straight, 7–28 mm, pubescent, trichomes appressed, branched. |
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, not appressed to rachis, not secund, usually curved, rarely straight, edges parallel, 4.5–11 cm × 1.5–2 mm; valves glabrous or sparsely pubescent throughout; ovules 140–190 per ovary; style 0.05–0.6 mm. |
Seeds | usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide. |
sub-biseriate, 1–1.3 × 0.7–0.8 mm; wing distal or, rarely, absent, 0.05–0.1 mm wide. |
Boechera paupercula |
Boechera shockleyi |
|
Phenology | Flowering Jun–Aug. | Flowering Apr–May. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Rock outcrops (primarily dolomite) and gravelly soil in desert scrub, sagebrush, and pinyon-juniper woodlands |
Elevation | 2400-3400 m (7900-11200 ft) | 1200-2200 m (3900-7200 ft) |
Distribution |
CA; ID; OR; WA; WY
|
CA; NV; UT
|
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 shockleyi is a distinctive sexual species recognizable by the combination of strongly overlapping cauline leaves, a dense covering of minute, 7–12-rayed trichomes, and relatively long, curved, divaricate-ascending fruits with sub-biseriate seeds. It is most similar to B. inyoensis, but differs from that species in its narrower (0.8–1.2 versus 1.2–2 mm) petals, eciliate basal leaves with smaller (0.1–0.2 versus 0.2–0.7 mm) trichomes, greater number (140–190 versus 74–134) of ovules per ovary, and shorter (1–1.3 versus 1.7–2 mm) seeds with distal (versus continuous) wings. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 406. |
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 shockleyi |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | (Munz) Dorn: Brittonia 55: 3. (2003) |
Web links |
|
|