Boechera subpinnatifida |
Boechera gracilipes |
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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). | Biennials or perennials; short-lived; sexual; 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, rarely arising laterally proximal to sterile shoots, 2.5–8.5 dm, densely pubescent proximally, trichomes simple or spurred, 0.9–1.5 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, 5–12 mm wide, margins shallowly dentate, sometimes ciliate near petiole base, surfaces sparsely to densely pubescent, trichomes short- to long-stalked, 2- or 3-rayed, usually 0.3–0.6 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
30–65, often concealing stem proximally; blade auricles 0.8–3 mm, surfaces of distalmost leaves usually glabrous. |
Racemes | 8–30-flowered, usually unbranched. |
(12–)15–50-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 pale lavender, 6–9 × 0.6–1 mm; valves glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
divaricate-ascending or horizontal, recurved, (15–)20–47 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. |
widely pendent, not appressed to rachis, not secund, curved, edges parallel, (2.5–)3–7.5 cm × 1.5–2.8 mm, glabrous; ovules 130–210 per ovary; style 0.2–0.5 mm. |
Seeds | uniseriate, 2.5–3.5 × 1.5–2.2 mm; wing continuous or at both ends, 0.4–0.8 mm wide. |
biseriate, 1.2–1.4 × 0.7–0.9 mm; wing continuous or distal, to 0.2 mm wide. |
2n | = 14. |
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Boechera subpinnatifida |
Boechera gracilipes |
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Phenology | Flowering Mar–May. | Flowering Apr–Jun. |
Habitat | Rock outcrops, talus, gravelly soil, often in sagebrush-grassland communities | Basalt, limestone, and sandy soils in ponderosa pine forests and pinyon-juniper woodlands |
Elevation | 800-2400 m (2600-7900 ft) | 1700-2300 m (5600-7500 ft) |
Distribution |
CA; ID; NV; OR; UT
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AZ; NV; 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.) |
Fruiting pedicel length, considered diagnostic by R. C. Rollins (1993) and N. H. Holmgren (2005b), occasionally fails to separate Boechera gracilipes from the closely-related B. fendleri. The two are consistently distinguished by trichome characters. In B. gracilipes, basal leaves usually lack prominent cilia and surfaces are persistently pubescent with at least some 3-rayed trichomes. Also, stems are rather densely pilose proximally, with the largest trichomes more than 0.9 mm. By contrast, basal leaves of B. fendleri always have prominent cilia, surfaces are often glabrescent, and 3-rayed trichomes usually are rare or absent. Stems of the latter are proximally hirsute to hispid, with the largest trichomes less than 0.9 mm. (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 gracilipes, Arabis arcuata var. longipes, Arabis perennans var. longipes |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (Greene) Dorn: Brittonia 55: 3. (2003) |
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