Boechera subpinnatifida |
Boechera falcatoria |
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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; apomictic; caudex sometimes 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 2–7 per caudex branch, arising from margin of rosette near ground surface, 0.5–2(–3) dm, densely pubescent proximally, trichomes simple and stalked, 2-rayed, 0.3–0.8 mm, 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 narrowly oblanceolate, 1–3 mm wide, margins entire, ciliate, trichomes to 1 mm, surfaces pubescent, trichomes stalked, 2–4-rayed, 0.3–0.8 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
3–7(–10), not concealing stem; blade auricles 0.2–1 mm, surfaces of distalmost leaves glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
6–15-flowered, 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 or lavender, 5–7 × 1.5–2.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
horizontal to divaricate-ascending, straight, 3–9 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. |
horizontal to divaricate-ascending, not appressed to rachis, not secund, usually strongly curved, edges parallel, 3.5–6.5 cm × 1.7–2 mm; valves glabrous; ovules 50–84 per ovary; style 0.05–0.5 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 × 1.1–1.5 mm; wing continuous, 0.1–0.2 mm wide. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera falcatoria |
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Phenology | Flowering Mar–May. | Flowering May–Jun. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Rock outcrops and gravelly soil in sagebrush and mountain shrub communities |
Elevation | 800-2400 m (2600-7900 ft) | 2000-2200 m (6600-7200 ft) |
Distribution |
CA; ID; NV; OR; UT
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UT |
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.) |
Of conservation concern. Although the exact parentage of Boechera falcatoria, an apomictic hybrid, remains in doubt, it is virtually certain that B. cusickii contributed at least one genome. Boechera falcatoria has been confused with both B. pendulina and B. perennans, but is amply distinct from both (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). Despite the proximity of the type locality to both Idaho and Nevada, the species is known only from northwestern Box Elder County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 409. | FNA vol. 7, p. 376. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis falcatoria |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (Rollins) Dorn: Brittonia 55: 3. (2003) |
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