Boechera repanda |
Boechera quebecensis |
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Greene's rockcress, Yosemite rockcress |
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Habit | Perennials; short- to long-lived; sexual; caudex usually not woody. | Biennials or perennials; short-lived; apomictic; caudex present or absent. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, (1–)2–9 dm, densely pubescent proximally, trichomes short- to long-stalked, 2–6-rayed, 0.2–0.5 mm, rarely mixed with simple ones, to 1.5 mm, glabrous or sparsely pubescent distally. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 1–4.5 dm, densely pubescent proximally, trichomes sessile, 2–4-rayed, 0.15–0.5 mm, glabrous distally. |
Basal leaves | blade broadly oblanceolate to obovate, 7–25(–50) mm wide, margins usually repand to coarsely dentate, rarely entire, not ciliate, surfaces moderately to densely pubescent, trichomes short- to long-stalked, 3–6-rayed, 0.2–0.5 mm. |
blade oblanceolate, 5–15 mm wide, margins denticulate, ciliate proximally, trichomes (simple), to 1 mm, surfaces moderately pubescent, trichomes subsessile, (2- or) 3–7-rayed, 0.1–0.3 mm. |
Cauline leaves | (3–)8–30, not concealing stem; blade auricles absent, surfaces of distalmost leaves sparsely pubescent. |
4–15, not concealing stem; blade auricles 1–3.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 7–25-flowered, sometimes branched. |
11–41-flowered, usually unbranched. |
Flowers | erect to ascending at anthesis; sepals glabrous or sparsely pubescent; petals white, 3.5–6 × 0.8–1 mm, glabrous; pollen ellipsoid. |
divaricate at anthesis; sepals pubescent; petals white, 6–7 × 1–2 mm, glabrous; pollen spheroid. |
Fruiting pedicels | erect to divaricate-ascending, straight, 3–10 mm, glabrous or pubescent, trichomes spreading, usually 2–5-rayed, rarely simple. |
horizontal to slightly descending, curved to straight, 3–8(–14) mm, glabrous or with some subappressed, branched trichomes. |
Fruits | divaricate-ascending, not appressed to rachis, not secund, usually curved, rarely straight, edges parallel, (3.5–)5–13.5 cm × 2.5–4 mm; valves glabrous or pubescent throughout; ovules 34–50 per ovary; style 0.5–1.5 mm. |
horizontal to slightly descending, not appressed to rachis, secund, straight, edges parallel, 3–6 cm × 1.5–2 mm; valves glabrous; ovules 56–94 per ovary. |
Seeds | uniseriate, 2.5–5(–6) × 2–3(–3.5) mm; wing continuous, 0.7–1.8 mm wide. |
uniseriate, 1.2–1.5 × 1–1.3 mm; wing continuous, 0.1–0.15 mm wide. |
2n | = 14. |
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Boechera repanda |
Boechera quebecensis |
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Phenology | Flowering Jun–Jul. | Flowering Jun–Jul. |
Habitat | Rock outcrops, talus, and gravelly soil in meadows and open pine forests | Calcareous rock outcrops and talus slopes |
Elevation | 1600-3500 m (5200-11500 ft) | 0-300 m (0-1000 ft) |
Distribution |
CA; NV
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QC |
Discussion | Boechera repanda is a sexual diploid that is distinguished from all other western North American species by its wide (10–50 mm), repand to coarsely dentate basal leaves. The form recognized as var. greenei appears to be a growth response to ecologically marginal habitats. Boechera repanda occurs sporadically in the Sierra Nevada and Transverse Ranges of California, and barely extends into the Carson Range in western Nevada. Arabis inamoena Greene (1911), not Greene (1908) is an illegitimate name, sometimes found in synonymy with Boechera repanda. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Morphological evidence suggests that Boechera quebecensis is an apomictic species that arose through hybridization between B. holboellii and B. stricta; it is most likely to be confused with B. grahamii (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 402. | FNA vol. 7, p. 401. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis repanda, Arabis repanda var. greenei | Arabis divaricarpa var. dechamplainii |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 388. (2003) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 246. (2007) |
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