Boechera subpinnatifida |
Boechera nevadensis |
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ashy rock-cress, Klamath rockcress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Perennials; short- to long-lived; sexual; caudex usually not woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4(–5) dm, densely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.1–0.2 mm, 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, 1–4(–5) mm wide, margins prominently dentate to subpinnatifid (leaf margins of sterile shoots often entire), ciliate near petiole base, trichomes (simple or 2-rayed), 0.4–0.6 mm, surfaces densely pubescent, trichomes short-stalked, (2–)4–9-rayed, 0.05–0.2 mm. |
blade oblanceolate, 2–6 mm wide, margins entire, rarely ciliate along petiole, trichomes (simple), 0.5–0.7 mm, surfaces glabrous. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
5–9, rarely concealing stem proximally; blade auricles 0.7–2.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
4–12-flowered, usually unbranched. |
Flowers | divaricate-ascending to pendent at anthesis; sepals pubescent; petals usually purple, rarely lavender, 9–14 × 1.5–3 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals glabrous; petals lavender, 4–5.5 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
divaricate-ascending to horizontal, straight, 2.5–8 mm, glabrous. |
Fruits | pendent, not appressed to rachis, not secund, straight to slightly curved, edges parallel, (3.5–)5–8 cm × (1.6–)2–3 mm; valves pubescent throughout; ovules 24–42 per ovary; style 0.5–1 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, 2.5–3.5 × 1.5–2.2 mm; wing continuous or at both ends, 0.4–0.8 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 subpinnatifida |
Boechera nevadensis |
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Phenology | Flowering Mar–May. | Flowering Jun. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Ledges and talus of limestone cliffs |
Elevation | 800-2400 m (2600-7900 ft) | 3000-3400 m (9800-11200 ft) |
Distribution |
CA; ID; NV; OR; UT
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NV |
Discussion | Originally thought to be restricted to northern California and adjacent Oregon, Boechera subpinnatifida is a sexual species that recently has been found in central Idaho, northern Nevada, and northwestern Utah. It appears to intergrade with both B. puberula and B. retrofracta, and species boundaries within this complex need further study. (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. 409. | FNA vol. 7, p. 391. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis nevadensis |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (Tidestrom) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 73. (2006) |
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