Boechera harrisonii |
Boechera crandallii |
|
---|---|---|
|
Crandall's rockcress |
|
Habit | Perennials; long-lived; (some-what cespitose); apomictic; caudex often woody. | Perennials; long-lived; (often cespitose); sexual; caudex somewhat woody. |
Stems | usually 3–7 per caudex branch, arising from margin of rosette near ground surface, 0.5–2.5 dm, usually sparsely pubescent proximally, rarely glabrous, trichomes short-stalked, 2- or 3-rayed, 0.06–0.2 mm, glabrous distally. |
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. |
Basal leaves | blade narrowly oblanceolate, 2–4 mm wide, margins entire or somewhat dentate, ciliate near petiole base, trichomes (simple), to 0.5 mm, surfaces sparsely pubescent, trichomes short-stalked, 2–5-rayed, 0.1–0.25 mm. |
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. |
Cauline leaves | 3–7, not concealing stem; blade auricles 0.5–1.5 mm, surfaces of distalmost leaves glabrous. |
5–14, not concealing stem; blade auricles 0.1–0.5 mm, surfaces of distalmost leaves pubescent. |
Racemes | 5–12-flowered, usually unbranched. |
10–30-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals lavender, 5–7.5 × 0.8–1.5 mm, glabrous; pollen spheroid. |
ascending at anthesis; sepals pubescent; petals usually white, 5–7 × 1–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | divaricate-ascending, straight, 8–12 mm, glabrous. |
ascending to divaricate-ascending, straight, 5–10 mm, pubescent, trichomes branched. |
Fruits | usually divaricate-ascending, rarely nearly horizontal, not appressed to rachis, not secund, curved to straight, edges parallel, 3–4.7 cm × 1–1.5 mm; valves glabrous; ovules 64–86 per ovary; style 0.2–0.5 mm. |
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. |
Seeds | uniseriate, 1.1–1.3 × 0.8–1.1 mm; wing continuous, 0.08–0.1 mm wide. |
uniseriate, 0.8–1 × 0.6–0.9 mm; wing continuous (rarely absent), to 0.1 mm wide. |
2n | = 14. |
|
Boechera harrisonii |
Boechera crandallii |
|
Phenology | Flowering May–Jun. | Flowering May–Jun. |
Habitat | Limestone and quartzite cliffs | Rocky slopes and gravelly soil in sagebrush, mountain shrub, open conifer forests |
Elevation | 1500-1600 m (4900-5200 ft) | 2000-2700 m (6600-8900 ft) |
Distribution |
UT |
CO
|
Discussion | Morphological evidence suggests that Boechera harrisonii is an apomictic species that arose through hybridization between B. microphylla and B. perennans (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). Boechera harrisonii is known only from Utah and Wasatch counties in north-central Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 383. | FNA vol. 7, p. 372. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis harrisonii, B. microphylla var. harrisonii | Arabis crandallii, Arabis stenoloba |
Name authority | (S. L. Welsh) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 266. (2007) | (B. L. Robinson) W. A. Weber: Phytologia 51: 369. (1982) |
Web links |