Boechera subpinnatifida |
Boechera acutina |
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ashy rock-cress, Klamath rockcress |
point rockcress, sharp-pod rock-cress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Biennials or perennials; short-lived; apomictic; caudex present or absent. |
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, 1.5–6 dm, densely pubescent proximally, trichomes sessile, 2–4-rayed, 0.15–0.4 mm, usually sparsely pubescent distally, rarely glabrous. |
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, 1.5–6 mm wide, margins usually entire, rarely denticulate, ciliate proximally, trichomes (simple), to 0.5 mm, surfaces sparsely to moderately pubescent, trichomes sessile, 3–5 (or 6)-rayed, 0.15–0.35 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
2–20(–38), often concealing stem proximally; blade auricles 0.3–2 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
5–20(–36)-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 or lavender, 5–7 × 0.9–1.3 mm, glabrous; pollen spheroid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
erect to ascending, usually straight, 3–10 mm, pubescent or glabrous, trichomes appressed, branched. |
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, not appressed to rachis, not secund, straight, edges parallel, 2.5–7.5 cm × 1.2–1.8 mm; valves glabrous; ovules 46–100 per ovary; style 0.3–1 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, 1.8–2.2 × 1–1.4 mm; wing continuous, 0.1–0.4 mm wide. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera acutina |
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Phenology | Flowering Mar–May. | Flowering Jun–Jul. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Gravelly slopes in meadows, open forests |
Elevation | 800-2400 m (2600-7900 ft) | 1400-1900 m (4600-6200 ft) |
Distribution |
CA; ID; NV; OR; UT
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CA; ID; OR |
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 acutina is an apomictic hybrid that clearly contains a genome derived from B. stricta; the other parent remains uncertain. Plants of B. acutina are superficially similar to B. pratincola and are often misidentified as Arabis (Boechera) divaricarpa; the species is easily distinguished from both of those (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. 365. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis acutina, Arabis divaricarpa var. interposita, Arabis drummondii var. interposita, Arabis interposita |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 236. (2007) |
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