Boechera crandallii |
Boechera nevadensis |
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Crandall's rockcress |
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Habit | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody. | Perennials; short- to long-lived; sexual; caudex usually not woody. |
Stems | usually 2–5 per caudex branch, arising from margin of rosette near ground surface, (1–)1.5–4 dm, densely pubescent proximally, trichomes short-stalked, 5–8-rayed, 0.1–0.2 mm, moderately to sparsely pubescent distally. |
usually 2–4 per caudex branch, arising from center of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–2 dm, glabrous throughout. |
Basal leaves | blade narrowly oblanceolate, 1.5–3(–5) mm wide, margins entire, ciliate along petiole base, trichomes (simple), to 0.6 mm, surfaces densely pubescent, trichomes short-stalked, 5–8-rayed 0.1–0.2 mm. |
blade oblanceolate, 2–6 mm wide, margins entire, rarely ciliate along petiole, trichomes (simple), 0.5–0.7 mm, surfaces glabrous. |
Cauline leaves | 5–14, not concealing stem; blade auricles 0.1–0.5 mm, surfaces of distalmost leaves pubescent. |
5–9, rarely concealing stem proximally; blade auricles 0.7–2.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 10–30-flowered, usually unbranched. |
4–12-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals usually white, 5–7 × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals glabrous; petals lavender, 4–5.5 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending to divaricate-ascending, straight, 5–10 mm, pubescent, trichomes branched. |
divaricate-ascending to horizontal, straight, 2.5–8 mm, glabrous. |
Fruits | ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 3–5.5 cm × 0.9–1.2 mm; valves glabrous; ovules 56–84 per ovary; style 0.1–0.5 mm. |
usually divaricate-ascending, rarely slightly descending, usually secund, straight to slightly curved, 1.9–4 cm × 2–3 mm; valves glabrous; ovules 52–72 per ovary; style 0.05–0.2 mm. |
Seeds | uniseriate, 0.8–1 × 0.6–0.9 mm; wing continuous (rarely absent), to 0.1 mm wide. |
biseriate, 1.1–1.4 × 0.8–1 mm; wing continuous, 0.07–0.15 mm wide. |
2n | = 14. |
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Boechera crandallii |
Boechera nevadensis |
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Phenology | Flowering May–Jun. | Flowering Jun. |
Habitat | Rocky slopes and gravelly soil in sagebrush, mountain shrub, open conifer forests | Ledges and talus of limestone cliffs |
Elevation | 2000-2700 m (6600-8900 ft) | 3000-3400 m (9800-11200 ft) |
Distribution |
CO
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NV |
Discussion | Of conservation concern. Boechera crandallii is a sexual diploid known only from the Gunnison Basin of west-central Colorado. Despite its narrow range, the species appears to hybridize frequently, most notably with B. pallidifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera nevadensis usually is treated as a synonym of Arabis pendulina (R. C. Rollins 1993) or B. demissa (N. H. Holmgren 2005b), but is amply distinct from both (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). It is known only from Clark and Nye counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 372. | FNA vol. 7, p. 391. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis crandallii, Arabis stenoloba | Arabis nevadensis |
Name authority | (B. L. Robinson) W. A. Weber: Phytologia 51: 369. (1982) | (Tidestrom) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 73. (2006) |
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