Boechera puberula |
Boechera pulchra |
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Blue Mountain rockcress, hoary rock-cress, silver rockcress |
beautiful rockcress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Perennials; long-lived; sexual; caudex 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 1 per caudex branch, arising from center of leaf tufts, elevated above ground surface on woody base, (1.5–)3–7.5 dm, densely pubescent proximally, trichomes short-stalked, usually 4–7-rayed, 0.1–0.3 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 linear to linear-oblanceolate, 1–3 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 4–9-rayed, 0.1–0.3 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
10–30, often concealing stem proximally; blade auricles absent or, rarely, to 0.5 mm, surfaces of distalmost leaves pubescent. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
8–25-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. |
descending at anthesis; sepals pubescent; petals usually purple, rarely white, 9–16 × 2–4(–5) mm, sparsely pubescent or glabrous (trichomes scattered abaxially); pollen ellipsoid. |
Fruiting pedicels | pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched. |
reflexed, abruptly recurved at base, otherwise straight, 8–16 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. |
strongly reflexed, often appressed to rachis, sometimes somewhat secund, straight, edges parallel, 3.3–8 cm × 2.5–4 mm; valves pubescent throughout; ovules 68–106 per ovary; style 0.1–0.3 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
biseriate, 1.7–2.8 × 1.5–2.2 mm; wing continuous, 0.25–0.65 mm wide. |
2n | = 14. |
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Boechera puberula |
Boechera pulchra |
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Phenology | Flowering Apr–Jul. | Flowering Mar–Jun. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Rocky, gravelly or sandy slopes in chaparral, sagebrush and desert scrub communities |
Elevation | 1300-2900 m (4300-9500 ft) | 800-2800 m (2600-9200 ft) |
Distribution |
CA; NV; OR; UT
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CA; NV; Mexico (Baja California)
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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.) |
Boechera pulchra is a distinctive diploid separated from related sexual species (B. formosa and B. lincolnensis) by abruptly recurved fruiting pedicels and purple flowers, and from apomictic hybrids (e.g., B. xylopoda) by having fruits densely pubescent throughout. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 399. | FNA vol. 7, p. 400. |
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 pulchra |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | (M. E. Jones ex S. Watson) W. A. Weber: Phytologia 51: 370. (1982) |
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