Boechera repanda |
Boechera texana |
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Greene's rockcress, Yosemite rockcress |
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Habit | Perennials; short- to long-lived; sexual; caudex usually not woody. | Perennials; long-lived; sexual; caudex woody. |
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, often slightly elevated above ground surface on woody base, 2–5 dm, glabrous throughout. |
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, 5–12 mm wide, margins dentate, ciliate (at least proximally), trichomes (usually simple), 1–2 mm, surfaces moderately pubescent, trichomes short-stalked, 2–4-rayed, 0.4–0.6 mm. |
Cauline leaves | (3–)8–30, not concealing stem; blade auricles absent, surfaces of distalmost leaves sparsely pubescent. |
5–12, often concealing stem proximally; blade auricles 1–2 mm, surfaces distally glabrous. |
Racemes | 7–25-flowered, sometimes branched. |
10–35-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-ascending at anthesis; sepals glabrous; petals white to lavender, 5–8 × 1.5–2 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect to divaricate-ascending, straight, 3–10 mm, glabrous or pubescent, trichomes spreading, usually 2–5-rayed, rarely simple. |
horizontal to divaricate-ascending, curved or angled downward, 10–20 mm, glabrous. |
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. |
widely pendent, not appressed to rachis, not secund, curved to nearly straight, edges parallel, 3.5–5 cm × 2.5–3 mm; valves glabrous; ovules 80–130 per ovary; style 0.2–0.7 mm. |
Seeds | uniseriate, 2.5–5(–6) × 2–3(–3.5) mm; wing continuous, 0.7–1.8 mm wide. |
biseriate, 1.1–1.3 × 0.9–1 mm; wing distal or continuous, 0.1–0.15 mm wide. |
2n | = 14. |
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Boechera repanda |
Boechera texana |
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Phenology | Flowering Jun–Jul. | Flowering Apr. |
Habitat | Rock outcrops, talus, and gravelly soil in meadows and open pine forests | Rock outcrops and gravelly soils in desert grassland and evergreen woodlands |
Elevation | 1600-3500 m (5200-11500 ft) | 1200-1700 m (3900-5600 ft) |
Distribution |
CA; NV
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NM; TX |
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.) |
Boechera texana is a sexual diploid included within Arabis fendleri var. fendleri by R. C. Rollins (1993), but it appears to be sufficiently distinct to warrant recognition at species level (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). There is little or no geographic overlap between the two, with B. texana confined to western Texas and southern New Mexico and B. fendleri ranging from western New Mexico and the Four Corners region through northern Arizona to southern Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 402. | FNA vol. 7, p. 409. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis repanda, Arabis repanda var. greenei | |
Name authority | (S. Watson) Al-Shehbaz: Novon 13: 388. (2003) | Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 85. (2006) |
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