Boechera puberula |
Boechera perstellata |
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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 short-lived; sexual; caudex not 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. |
usually 2–5 per plant, arising from margin of rosette near ground surface, (1–)2–8 dm, densely pubescent proximally, trichomes short-stalked, 3- or 4-rayed, 0.1–0.5 mm, similarly pubescent distally. |
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 obovate to oblanceolate, (5–)10–45 mm wide, margins usually coarsely dentate, rarely sinuate, ciliate on petiole base, surfaces moderately pubescent, trichomes short-stalked, 3- or 4(–6)-rayed, 0.1–0.5 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
6–25, concealing stem proximally; blade auricles 1–6 mm, surfaces of distalmost leaves pubescent. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
10–40-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. |
ascending at anthesis; sepals pubescent; petals purplish, 3–4 × 0.7–1 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched. |
usually horizontal, usually straight, rarely slightly curved, 5–15 mm, pubescent, trichomes spreading, simple. |
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. |
usually horizontal, not appressed to rachis, not secund, straight, edges parallel, (1.5–)2–3.3 cm × 0.8–1 mm; valves sparsely pubescent throughout; ovules 12–20 per ovary; style 0.4–0.8 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
uniseriate, 0.8–1.1 × 0.6–0.8 mm, not winged. |
2n | = 14. |
= 14. |
Boechera puberula |
Boechera perstellata |
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Phenology | Flowering Apr–Jul. | Flowering Apr–May. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Calcareous bluffs and wooded hillsides |
Elevation | 1300-2900 m (4300-9500 ft) | 200-400 m (700-1300 ft) |
Distribution |
CA; NV; OR; UT
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KY; TN |
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 perstellata 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. 396. |
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 perstellata, Arabis perstellata var. ampla |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | (E. L. Braun) Al-Shehbaz: Novon 13: 388. (2003) |
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