Boechera rectissima |
Boechera rollinsiorum |
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bristly-leaf rock-cress |
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Habit | Biennials or perennials; short-lived; sexual; caudex present or absent. | Perennials; long-lived; sexual; caudex woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 2–8(–10) dm, usually glabrous proximally, rarely sparsely pubescent, trichomes simple, to 0.7 mm, glabrous distally. |
usually 3–5 per caudex branch, arising from margin of rosette, elevated above ground surface on woody base, 1–2.5 dm, densely pubescent proximally, trichomes short-stalked, 2–4 (or 5)-rayed, 0.2–0.4 mm, moderately to sparsely pubescent distally. |
Basal leaves | blade oblanceolate, 3–8(–13) mm wide, margins entire or denticulate, ciliate, trichomes (simple), 0.5–1.2 mm, surfaces sparsely to densely pubescent, trichomes simple, to 0.8 mm, often mixed with short-stalked, 2- or 3-rayed ones, 0.15–0.5 mm. |
blade oblanceolate, 3–5 mm wide, margins entire, ciliate proximally, trichomes (simple), to 0.6 mm, surfaces densely pubescent, trichomes short-stalked, 2–4 (or 5)-rayed, 0.15–0.4 mm. |
Cauline leaves | 6–30(–45), often concealing stem proximally; blade auricles 1–1.5 mm, surfaces of distalmost leaves sparsely pubescent, sometimes margins ciliate. |
5–9, not concealing stem; blade auricles 0.5–1 mm, surfaces of distalmost leaves sparsely to moderately pubescent. |
Racemes | 10–30(–50)-flowered, usually unbranched. |
5–11-flowered, usually unbranched. |
Flowers | pendent at anthesis; sepals pubescent; petals white, 3–4 × 0.7–1.2 mm, glabrous; pollen ellipsoid. |
divaricate-ascending at anthesis; sepals pubescent; petals pale purple, 6–8 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, abruptly recurved at base, otherwise straight, 4–10 mm, glabrous. |
descending, straight to slightly recurved, 4–6 mm, pubescent, trichomes appressed, branched. |
Fruits | strongly reflexed, usually appressed to rachis, not secund, straight, edges parallel, 5–9 cm × 1.8–2.5 mm; valves glabrous; ovules 46–80 per ovary; style 0.2–0.8 mm. |
(immature) pendent, not appressed to rachis, not secund, straight, edges parallel; valves glabrous. |
Seeds | uniseriate, 1.8–2.1 × 1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
not seen. |
Boechera rectissima |
Boechera rollinsiorum |
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Phenology | Flowering May–Jul. | Flowering Jun. |
Habitat | Rocky slopes in open conifer forests | Metamorphosed igneous gravel on steep slopes |
Elevation | 1500-2500 m (4900-8200 ft) | ca. 2100 m (ca. 6900 ft) |
Distribution |
CA; OR
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ID |
Discussion | Boechera rectissima is easily recognized by its combination of glabrous stems, basal leaves with large, predominantly simple trichomes, short (3–4 mm), white petals, and strongly reflexed, appressed fruits. Plants assigned to var. simulans appear to be hybrids between this species and B. retrofracta. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera rollinsiorum shows superficial similarities to both B. glareosa and B. lasiocarpa (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). It is known thus far only from the type collection below Galena Summit in central Idaho. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 401. | FNA vol. 7, p. 403. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis rectissima, Arabis setigera, Arabis wyndii | |
Name authority | (Greene) Al-Shehbaz: Novon 13: 388. (2003) | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 81. (2006) |
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