Boechera tularensis |
Boechera rollei |
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Tulare rockcress |
Rolle's rock-cress |
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Habit | Biennials or perennials; short-lived; apomictic; caudex present or absent. | Perennials; long-lived; sexual; caudex woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 2–7 dm, sparsely to densely pubescent proximally, trichomes subsessile, sub-malpighiaceous, 0.3–0.6 mm, glabrous distally. |
usually 1 per caudex branch, arising from center of rosette, elevated above ground surface on woody base, 1.5–2.5 dm, glabrous throughout. |
Basal leaves | blade oblanceolate, 3–7 mm wide, margins entire, ciliate proximally, trichomes (simple), to 0.8 mm, surfaces sparsely to densely pubescent, trichomes subsessile, 2–5-rayed, 0.2–0.55 mm. |
blade oblanceolate, 3–8 mm wide, margins entire, ciliate proximally, trichomes (simple), 0.2–0.7 mm, surfaces glabrous or sparsely pubescent, trichomes short-stalked, 2–4-rayed, 0.2–0.4 mm. |
Cauline leaves | 7–17, often concealing stem proximally; blade auricles 2–5 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
6–12, sometimes concealing stem proximally; blade auricles 0.5–2.5 mm, surfaces of distalmost leaves glabrous. |
Racemes | 19–39-flowered, usually unbranched. |
3–7-flowered, unbranched. |
Flowers | divaricate to pendent at anthesis; sepals pubescent; petals white to pale lavender, 6–7 × 1.2–2 mm, glabrous; pollen spheroid. |
divaricate-ascending at anthesis; sepals glabrous; petals creamy white, 8–11 × 2–2.5 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | reflexed, recurved proximally, 5–13 mm, glabrous. |
strongly curved proximally, 4–6 mm, glabrous. |
Fruits | reflexed, rarely appressed to rachis, not secund, straight, edges parallel, 4–7(–8.5) cm × 2–2.3 mm; valves glabrous; ovules 88–104 per ovary; style 0.3–0.7 mm. |
pendent, not appressed to rachis, not secund, straight to slightly curved, edges undulate (not parallel), 3.5–6 cm × 2.5–3.5 mm; valves glabrous; ovules 14–22 per ovary; style 0.5–1 mm. |
Seeds | sub-biseriate, 2–2.5 × 1.1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
uniseriate, 3–4 × 1.5–2 mm; wing distal and proximal, 0.3–0.6 mm wide. |
Boechera tularensis |
Boechera rollei |
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Phenology | Flowering Jun–Jul. | Flowering Aug. |
Habitat | Rocky slopes in montane and subalpine habitats | Peridotite rocks on sparsely forested slopes |
Elevation | 2400-3200 m (7900-10500 ft) | 1600-1800 m (5200-5900 ft) |
Distribution |
CA |
CA |
Discussion | Morphological evidence suggests that Boechera tularensis is an apomictic species that contains three different genomes, one each from B. rectissima, B. retrofracta, and B. stricta. It is most often confused with B. pinetorum and B. retrofracta, but is easily distinguishable from both (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison). It is known from the southern Sierra Nevada (Fresno and Tulare counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Boechera rollei is easily distinguished from the habitally similar B. suffrutescens by its longer (8–11 versus 4.5–6 mm) petals, narrower (2.5–3.5 versus 3–6 mm) fruits, and narrower (0.3–0.6 versus 0.8–1.5 mm) seed wings. This distinctive sexual species is known only from the vicinity of the type locality on the divide between the Applegate and Klamath Rivers in Siskiyou County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 410. | FNA vol. 7, p. 403. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis rollei | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 249. (2007) | (Rollins) Al-Shehbaz: Novon 13: 389. (2003) |
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