Boechera puberula |
Boechera rectissima |
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Blue Mountain rockcress, hoary rock-cress, silver rockcress |
bristly-leaf rock-cress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | 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–)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 rosette near ground surface, 2–8(–10) dm, usually glabrous proximally, rarely sparsely pubescent, trichomes simple, to 0.7 mm, glabrous 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 oblanceolate, 3–8(–13) mm wide, margins entire or denticulate, ciliate, trichomes (simple), 0.5–1.2 mm, surfaces sparsely to densely pubescent, trichomes simple, to 0.8 mm, often mixed with short-stalked, 2- or 3-rayed ones, 0.15–0.5 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
6–30(–45), often concealing stem proximally; blade auricles 1–1.5 mm, surfaces of distalmost leaves sparsely pubescent, sometimes margins ciliate. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
10–30(–50)-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. |
pendent at anthesis; sepals pubescent; petals white, 3–4 × 0.7–1.2 mm, glabrous; 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, 4–10 mm, glabrous. |
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, usually appressed to rachis, not secund, straight, edges parallel, 5–9 cm × 1.8–2.5 mm; valves glabrous; ovules 46–80 per ovary; style 0.2–0.8 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
uniseriate, 1.8–2.1 × 1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
2n | = 14. |
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Boechera puberula |
Boechera rectissima |
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Phenology | Flowering Apr–Jul. | Flowering May–Jul. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Rocky slopes in open conifer forests |
Elevation | 1300-2900 m (4300-9500 ft) | 1500-2500 m (4900-8200 ft) |
Distribution |
CA; NV; OR; UT
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CA; OR
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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 rectissima is easily recognized by its combination of glabrous stems, basal leaves with large, predominantly simple trichomes, short (3–4 mm), white petals, and strongly reflexed, appressed fruits. Plants assigned to var. simulans appear to be hybrids between this species and B. retrofracta. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 399. | FNA vol. 7, p. 401. |
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 rectissima, Arabis setigera, Arabis wyndii |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | (Greene) Al-Shehbaz: Novon 13: 388. (2003) |
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