Boechera subpinnatifida |
Boechera gracilenta |
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ashy rock-cress, Klamath rockcress |
Selby's rockcress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Perennials; short- or (rarely) long-lived; apomictic; 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. |
1–9 per caudex branch, arising from center or margin of rosette near ground surface, (1.5–)2.5–5.5 dm, densely pubescent proximally, trichomes short-stalked, 2–4-rayed, 0.1–0.5 mm, mixed with some simple ones, to 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 oblanceolate, 2–9 mm wide, margins shallowly dentate or sometimes entire, ciliate proximally, trichomes (simple and spurred), to 1.2 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–6(–8)-rayed, 0.1–0.5 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
4–9, not concealing stem; blade auricles 1–3 mm, surfaces of distalmost leaves usually glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
7–20-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 lavender, 6–7 × 1.5–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
divaricate-ascending, gently curved downward, (7–)10–18 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 widely pendent, rarely horizontal, not appressed to rachis, not secund, slightly curved, edges parallel, (3–)4.5–7 cm × 1.7–2 mm; valves glabrous; ovules 60–96 per ovary; style 0.1–0.3 mm. |
Seeds | uniseriate, 2.5–3.5 × 1.5–2.2 mm; wing continuous or at both ends, 0.4–0.8 mm wide. |
sub-biseriate, 1.2–1.8 × 0.9–1.2 mm; wing continuous, 0.1–0.25 mm wide. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera gracilenta |
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Phenology | Flowering Mar–May. | Flowering Apr–May. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Rocky slopes and sandy soil in pinyon-juniper woodlands and mountain shrub communities |
Elevation | 800-2400 m (2600-7900 ft) | 1900-2300 m (6200-7500 ft) |
Distribution |
CA; ID; NV; OR; UT
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AZ; CO; NM; UT
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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.) |
Morphological evidence suggests that Boechera gracilenta is an apomictic species that arose through hybridization between B. fendleri and B. pallidifolia; it is superficially similar to the sexual diploid B. perennans but is not closely related (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 409. | FNA vol. 7, p. 381. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis gracilenta, Arabis selbyi, B. selbyi |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 240. (2007) |
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