Boechera subpinnatifida |
Boechera lignifera |
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ashy rock-cress, Klamath rockcress |
desert rockcress |
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Habit | Perennials; long-lived; sexual; caudex woody (often with persistent, crowded leaf bases). | Perennials; short- to long-lived; apomictic or 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 2–5 per caudex branch, arising laterally proximal to sterile shoots, often elevated on woody base, 1.2–4(–5) dm, densely pubescent proximally, trichomes short-stalked, 4–7-rayed, 0.1–0.3 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 narrowly oblanceolate, 2–5(–8) mm wide, margins entire, rarely ciliate near petiole base, trichomes (simple or spurred), to 1 mm, surfaces densely pubescent, trichomes short-stalked, 3–7-rayed, 0.05–0.3 mm. |
Cauline leaves | (10–)20–60, often concealing stem throughout; blade auricles 0.5–3 mm, surfaces of distalmost leaves moderately to sparsely pubescent. |
4–12(–17), rarely concealing stem proximally; blade auricles 0.5–2 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 8–30-flowered, usually unbranched. |
6–15(–25)-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. |
divaricate-ascending at anthesis; sepals pubescent; petals whitish (often aging pale lavender), 5–7 × 1–1.5 mm, glabrous; pollen ellipsoid or spheroid. |
Fruiting pedicels | reflexed, strongly recurved, 5–15 mm, pubescent, trichomes appressed, branched. |
slightly descending, gently recurved, 5–16 mm, glabrous or sparsely pubescent, 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. |
widely pendent, not appressed to rachis, not secund, usually curved, edges parallel, 2.5–5.6 cm × 1.2–2 mm; valves glabrous; ovules 48–74 per ovary; style 0.1–0.2 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, 1–1.3 × 0.8–1 mm; wing often continuous, 0.1–0.15 mm wide. |
2n | = 14. |
= 14. |
Boechera subpinnatifida |
Boechera lignifera |
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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 sagebrush 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; CO; ID; NM; UT; WY
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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.) |
Boechera lignifera is commonly found on stabilized sand dunes. The related B. cobrensis often is found in similar habitats, and the two species can be difficult to distinguish where their ranges overlap in Idaho and Wyoming. It is possible that B. cobrensis was involved in the origin of some apomictic populations currently assigned to B. lignifera. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 409. | FNA vol. 7, p. 388. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis subpinnatifida | Arabis lignifera |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 389. (2003) | (A. Nelson) W. A. Weber: Phytologia 51: 370. (1982) |
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