Boechera puberula |
Boechera fecunda |
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Blue Mountain rockcress, hoary rock-cress, silver rockcress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Perennials; usually long-lived; sexual; caudex often woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, (1–)2–6.3 dm, densely pubescent proximally, trichomes short-stalked, 3–8-rayed, 0.1–0.3(–0.5) mm, similarly pubescent distally. |
1 to several per caudex branch, arising from center and margin of rosette, slightly elevated on woody base or from near ground surface, 0.8–3 dm, densely pubescent throughout, trichomes short-stalked, 5–10-rayed, 0.1–0.2 mm. |
Basal leaves | blade oblanceolate to linear-oblanceolate, 1.5–5 mm wide, margins usually dentate, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5–12-rayed, 0.05–0.2 mm. |
blade linear-oblanceolate, 1–5 mm wide, margins entire or with few teeth subapically, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5–10-rayed, 0.1–0.2 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
5–18, concealing stem proximally; blade auricles 0.5–2.5 mm, surfaces of distalmost leaves densely pubescent. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
8–35-flowered, usually unbranched. |
Flowers | ascending to descending at anthesis; sepals pubescent; petals white to lavender, 5–9 × 0.8–1.8 mm, glabrous; pollen ellipsoid. |
erect to ascending at anthesis; sepals pubescent; petals purplish, 8–12 × 2.5–4.5 mm; pollen ellipsoid. |
Fruiting pedicels | pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched. |
erect to ascending, straight, 5–15 mm, pubescent, trichomes appressed, branched. |
Fruits | closely pendent, rarely appressed to rachis, sometimes somewhat secund, usually straight, edges parallel, 3–6.5 cm × 1.9–2.2 mm; valves pubescent throughout; ovules 38–64 per ovary; style 0.05–0.1 mm. |
erect to ascending, often appressed to rachis, not secund, straight, edges parallel, 3–5.8 cm × 1.4–1.8 mm; valves densely pubescent throughout; ovules 34–68 per ovary; style 1–1.5 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
uniseriate, 1–1.5 × 0.8–1.2 mm; wing continuous, 0.5–0.1 mm wide. |
2n | = 14. |
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Boechera puberula |
Boechera fecunda |
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Phenology | Flowering Apr–Jul. | Flowering Apr–Jun. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Rocky ground in sagebrush areas |
Elevation | 1300-2900 m (4300-9500 ft) | 1200-1800 m (3900-5900 ft) |
Distribution |
CA; NV; OR; UT
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MT |
Discussion | Boechera puberula is a diploid species that appears to intergrade with both B. retrofracta and B. subpinnatifida. The glabrous-fruited specimens discussed by R. C. Rollins (1993) represent apomictic hybrids with other species, primarily B. pendulocarpa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Boechera fecunda is a distinctive sexual species known from Ravali and Silver Bow counties. Boechera fecunda is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 399. | FNA vol. 7, p. 377. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis puberula, Arabis arida, Arabis beckwithii, Arabis lignipes var. impar, Arabis sabulosa, Arabis subpinnatifida var. beckwithii, Arabis subpinnatifida var. impar, B. beckwithii | Arabis fecunda |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | (Rollins) Dorn: Brittonia 55: 3. (2003) |
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