Boechera crandallii |
Boechera hoffmannii |
|
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Crandall's rockcress |
Hoffmann's rockcress |
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Habit | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody. | Perennials; long-lived; sexual; caudex woody (sometimes with persistent, crowded leaf bases). |
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, often elevated above ground surface on woody base, 5–7 dm, glabrous or sparsely pubescent proximally, trichomes short-stalked, 2- or 3-rayed, 0.15–0.4 mm, glabrous or sparsely pubescent 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, 3–8 mm wide, margins coarsely dentate, ciliate, trichomes (simple and 2-rayed), to 0.6 mm, surfaces sparsely to densely pubescent, trichomes short-stalked, 2–7-rayed, 0.15–0.4 mm. |
Cauline leaves | 5–14, not concealing stem; blade auricles 0.1–0.5 mm, surfaces of distalmost leaves pubescent. |
15–65, concealing stem; blade auricles 1–4 mm, surfaces of distalmost leaves pubescent. |
Racemes | 10–30-flowered, usually unbranched. |
30–70-flowered, sometimes branched. |
Flowers | ascending at anthesis; sepals pubescent; petals usually white, 5–7 × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals white or pale lavender, 8–10 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | ascending to divaricate-ascending, straight, 5–10 mm, pubescent, trichomes branched. |
divaricate-ascending, straight, 10–45 mm, glabrous. |
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, rarely straight, edges parallel, 6–10 cm × 2.5–3 mm; valves glabrous; ovules 170–220 per ovary; style 0.05–0.5 mm. |
Seeds | uniseriate, 0.8–1 × 0.6–0.9 mm; wing continuous (rarely absent), to 0.1 mm wide. |
biseriate, 1.2–1.6 × 0.9–1.2 mm; wing continuous, 0.1–0.2 mm wide. |
2n | = 14. |
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Boechera crandallii |
Boechera hoffmannii |
|
Phenology | Flowering May–Jun. | Flowering Feb–Mar. |
Habitat | Rocky slopes and gravelly soil in sagebrush, mountain shrub, open conifer forests | Sea cliff ledges and crevices of volcanic outcrop in chaparral communities |
Elevation | 2000-2700 m (6600-8900 ft) | 0-100 m (0-300 ft) |
Distribution |
CO
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CA |
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.) |
Of conservation concern. Boechera hoffmannii is a distinctive sexual species that appears to be restricted to Santa Cruz Island in Santa Barbara County. It is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 372. | FNA vol. 7, p. 383. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis crandallii, Arabis stenoloba | Arabis maxima var. hoffmannii, Arabis hoffmannii |
Name authority | (B. L. Robinson) W. A. Weber: Phytologia 51: 369. (1982) | (Munz) Al-Shehbaz: Novon 13: 386. (2003) |
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