Boechera puberula |
Boechera tularensis |
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Blue Mountain rockcress, hoary rock-cress, silver rockcress |
Tulare rockcress |
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Habit | Perennials; short-lived; sexual; caudex not woody. | Biennials or perennials; short-lived; apomictic; 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, 2–7 dm, sparsely to densely pubescent proximally, trichomes subsessile, sub-malpighiaceous, 0.3–0.6 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, 3–7 mm wide, margins entire, ciliate proximally, trichomes (simple), to 0.8 mm, surfaces sparsely to densely pubescent, trichomes subsessile, 2–5-rayed, 0.2–0.55 mm. |
Cauline leaves | 7–45(–65), concealing stem proximally; blade auricles absent or 0.7–3 mm, surfaces of distalmost leaves pubescent. |
7–17, often concealing stem proximally; blade auricles 2–5 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
Racemes | 10–40(–64)-flowered, usually unbranched. |
19–39-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. |
divaricate to pendent at anthesis; sepals pubescent; petals white to pale lavender, 6–7 × 1.2–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | pendent, recurved distal to horizontal to ascending base, 4–10 mm, pubescent, trichomes appressed, branched. |
reflexed, recurved proximally, 5–13 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. |
reflexed, rarely appressed to rachis, not secund, straight, edges parallel, 4–7(–8.5) cm × 2–2.3 mm; valves glabrous; ovules 88–104 per ovary; style 0.3–0.7 mm. |
Seeds | uniseriate, 1.4–1.8 × 1–1.4 mm; wing continuous, 0.1–0.3 mm wide. |
sub-biseriate, 2–2.5 × 1.1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
2n | = 14. |
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Boechera puberula |
Boechera tularensis |
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Phenology | Flowering Apr–Jul. | Flowering Jun–Jul. |
Habitat | Ledges, rocky slopes, gravelly hillsides in sagebrush, pinyon-juniper, and mountain shrub communities | Rocky slopes in montane and subalpine habitats |
Elevation | 1300-2900 m (4300-9500 ft) | 2400-3200 m (7900-10500 ft) |
Distribution |
CA; NV; OR; UT
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CA |
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.) |
Morphological evidence suggests that Boechera tularensis is an apomictic species that contains three different genomes, one each from B. rectissima, B. retrofracta, and B. stricta. It is most often confused with B. pinetorum and B. retrofracta, but is easily distinguishable from both (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). It is known from the southern Sierra Nevada (Fresno and Tulare counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 399. | FNA vol. 7, p. 410. |
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 | |
Name authority | (Nuttall) Dorn: Brittonia, 55: 3. (2003) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 249. (2007) |
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