Boechera crandallii |
Boechera breweri |
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Crandall's rockcress |
Brewer's rock-cress |
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Habit | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody. | Perennials; long-lived; sexual; caudex woody. | ||||
Stems | usually 2–5 per caudex branch, arising from margin of rosette near ground surface, (1–)1.5–4 dm, densely pubescent proximally, trichomes short-stalked, 5–8-rayed, 0.1–0.2 mm, moderately to sparsely pubescent distally. |
usually 1 per caudex branch, arising from center of rosette, somewhat elevated on woody base or from ground surface, 0.6–3.5(–4.5) dm, densely pubescent proximally, trichomes long-stalked and simple, 2-rayed (sometimes all simple), 0.4–1 mm, sparsely pubescent or glabrous distally. |
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Basal leaves | blade narrowly oblanceolate, 1.5–3(–5) mm wide, margins entire, ciliate along petiole base, trichomes (simple), to 0.6 mm, surfaces densely pubescent, trichomes short-stalked, 5–8-rayed 0.1–0.2 mm. |
blade oblanceolate, 3–7(–11) mm wide, margins entire or dentate, ciliate proximally, trichomes to 1 mm, surfaces densely pubescent, trichomes long-stalked, 2–4-rayed, 0.4–0.8 mm. |
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Cauline leaves | 5–14, not concealing stem; blade auricles 0.1–0.5 mm, surfaces of distalmost leaves pubescent. |
5–15(–28), often concealing stem proximally; blade auricles 0.5–3(–5) mm, surfaces of distalmost leaves pubescent. |
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Racemes | 10–30-flowered, usually unbranched. |
7–20(–30)-flowered, usually unbranched. |
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Flowers | ascending at anthesis; sepals pubescent; petals usually white, 5–7 × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals usually purple (rarely lavender), 7–12 × 2–4 mm, glabrous; pollen ellipsoid. |
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Fruiting pedicels | ascending to divaricate-ascending, straight, 5–10 mm, pubescent, trichomes branched. |
ascending to divaricate-ascending, straight, 3–25 mm, pubescent or glabrous, trichomes spreading, simple and 2-rayed. |
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Fruits | ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 3–5.5 cm × 0.9–1.2 mm; valves glabrous; ovules 56–84 per ovary; style 0.1–0.5 mm. |
ascending to divaricate-ascending, not appressed to rachis, not secund, usually curved, rarely straight, edges parallel, 3.5–10 cm × 1.5–2.2 mm; valves usually glabrous, rarely sparsely pubescent; ovules 48–96 per ovary; style 0.05–0.3 mm. |
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Seeds | uniseriate, 0.8–1 × 0.6–0.9 mm; wing continuous (rarely absent), to 0.1 mm wide. |
uniseriate, 1.2–1.7 × 1–1.2 mm; wing continuous, 0.1–0.2 mm wide distally. |
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2n | = 14. |
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Boechera crandallii |
Boechera breweri |
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Phenology | Flowering May–Jun. | |||||
Habitat | Rocky slopes and gravelly soil in sagebrush, mountain shrub, open conifer forests | |||||
Elevation | 2000-2700 m (6600-8900 ft) | |||||
Distribution |
CO
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CA; OR
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Discussion | Of conservation concern. Boechera crandallii is a sexual diploid known only from the Gunnison Basin of west-central Colorado. Despite its narrow range, the species appears to hybridize frequently, most notably with B. pallidifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). Relatively few other sexual diploid species of Boechera co-occur with B. breweri, and the only currently recognized hybrid involving this taxon is B. rubicundula (= B. arcuata × B. breweri; M. D. Windham and I. A. Al-Shehbaz 2007). Boechera breweri appears to be related to B. sparsiflora, and some specimens of subsp. shastaensis can be difficult to separate from that species. The two subspecies appear to intergrade on the western side of the Sacramento Valley from Tehama to Solano counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 7, p. 372. | FNA vol. 7, p. 367. | ||||
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Arabis crandallii, Arabis stenoloba | Arabis breweri, Arabis breweri var. figularis, Arabis epilobioides | ||||
Name authority | (B. L. Robinson) W. A. Weber: Phytologia 51: 369. (1982) | (S. Watson) Al-Shehbaz: Novon 13: 384. (2003) | ||||
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