Boechera subpinnatifida |
Boechera cusickii |
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ashy rock-cress, Klamath rockcress |
Cusick's rock-cress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Perennials; long-lived; (often cespitose); sexual; caudex usually 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 1 per caudex branch, arising from center of rosette near ground surface, 1–2.5(–3.8) dm, densely pubescent proximally, trichomes simple, 0.5–1.5 mm, sparsely pubescent or glabrous distally. |
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 linear to narrowly oblanceolate, 0.5–2 mm wide, margins entire, ciliate, trichomes (simple), 1–1.7 mm, surfaces moderately pubescent, trichomes simple and long-stalked, 2-rayed, 0.5–1.7 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
10–30, often concealing stem proximally; blade auricles 0–0.5 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 8–30-flowered, usually unbranched. |
5–14-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 pubescent; petals white to lavender, 6–10 × 2–3 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
ascending, straight, 4–15(–20) mm, glabrous or sparsely pubescent, trichomes simple. |
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. |
ascending to divaricate-ascending, not appressed to rachis, not secund, straight or curved, edges parallel, 4–8(–9.5) cm × 2.3–3 mm; valves glabrous; ovules 56–106 per ovary; style 0.1–0.5 mm. |
Seeds | uniseriate, 2.5–3.5 × 1.5–2.2 mm; wing continuous or at both ends, 0.4–0.8 mm wide. |
uniseriate, 1.5–2.5 × 1.5–2 mm; wing continuous, 0.1–0.2 mm wide distally. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera cusickii |
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Phenology | Flowering Mar–May. | Flowering Apr-mid May. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Basaltic bluffs, rocky slopes, rock crevices, gravelly hillsides, sagebrush hills, outcrops of volcanic rock |
Elevation | 800-2400 m (2600-7900 ft) | 600-1800 m (2000-5900 ft) |
Distribution |
CA; ID; NV; OR; UT
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ID; NV; OR; WA
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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.) |
Peripheral populations of Boechera cusickii in south-central Idaho and northern Nevada have a higher proportion of branched hairs, possibly resulting from hybridization with B. sparsiflora. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 409. | FNA vol. 7, p. 372. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis cusickii |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (S. Watson) Al-Shehbaz: Novon 13: 384. (2003) |
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