Boechera crandallii |
Boechera glareosa |
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Crandall's rockcress |
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Habit | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody. | Perennials; short- to long-lived; sexual; caudex usually not 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 2–6 per caudex branch, arising from margin of rosette near ground surface, 0.8–4 dm, densely pubescent proximally, trichomes simple and short-stalked, 2-rayed, 0.3–0.6 mm, glabrous distally. |
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 narrowly oblanceolate, 1–5 mm wide, margins entire or few-toothed, ciliate proximally, trichomes (simple), to 0.9 mm, surfaces densely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.3–0.5 mm. |
Cauline leaves | 5–14, not concealing stem; blade auricles 0.1–0.5 mm, surfaces of distalmost leaves pubescent. |
3–6, not concealing stem; blade auricles 0.3–0.6 mm, surfaces of distalmost leaves glabrous. |
Racemes | 10–30-flowered, usually unbranched. |
7–15-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals usually white, 5–7 × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals lavender, 3.5–6 × 1–1.5 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending to divaricate-ascending, straight, 5–10 mm, pubescent, trichomes branched. |
divaricate-ascending to horizontal, straight or gently recurved, 4–10 mm, glabrous or sparsely pubescent, trichomes spreading. |
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. |
divaricate-ascending to horizontal, not appressed to rachis, not secund, usually curved or straight, edges parallel, 2.5–4 cm × 1.2–1.5 mm; valves glabrous; ovules 50–80 per ovary; style 0.05–0.3 mm. |
Seeds | uniseriate, 0.8–1 × 0.6–0.9 mm; wing continuous (rarely absent), to 0.1 mm wide. |
uniseriate, 1–1.5 × 0.7–1 mm; wing usually distal, ca. 0.1 mm wide. |
2n | = 14. |
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Boechera crandallii |
Boechera glareosa |
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Phenology | Flowering May–Jun. | Flowering May–Jun. |
Habitat | Rocky slopes and gravelly soil in sagebrush, mountain shrub, open conifer forests | Conglomerate and limestone outcrops in pinyon-juniper and mountain shrub-conifer communities |
Elevation | 2000-2700 m (6600-8900 ft) | 2000-2600 m (6600-8500 ft) |
Distribution |
CO
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CO; UT |
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.) |
Specimens of Boechera glareosa originally were identified as Arabis microphylla var. macounii (= B. macounii) by R. C. Rollins. The former (a sexual species) is distinguished from the latter (an apomictic hybrid) by having wider (1–2 versus 0.5–0.8 mm) petals, fewer (2–9 versus mostly 9–16) cauline leaves, and fewer (7–15 versus 10–33) flowers per inflorescence. Boechera glareosa is known only from Moffat County, Colorado, and Summit and Uintah counties, Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 372. | FNA vol. 7, p. 380. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis crandallii, Arabis stenoloba | |
Name authority | (B. L. Robinson) W. A. Weber: Phytologia 51: 369. (1982) | Dorn: Brittonia 55: 1, fig. 1. (2003) |
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