Boechera tularensis |
Boechera pendulina |
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Tulare rockcress |
nodding rock cress, rabbit-ear rockcress |
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Habit | Biennials or perennials; short-lived; apomictic; caudex present or absent. | Perennials; short- to long-lived; sexual or apomictic; caudex sometimes 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 2–6 per caudex branch, arising from margin of rosette near ground surface, or arising laterally proximal to sterile shoots, 0.6–3(–3.7) dm, sparsely to densely pubescent proximally, trichomes simple, 0.3–0.8 mm, glabrous distally. |
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 to obovate, 1.5–6 mm wide, margins usually entire, rarely dentate, ciliate throughout, trichomes (usually simple), 0.4–1 mm, surfaces pubescent, trichomes simple and short- and long-stalked, 2-rayed, 0.3–0.8 mm. |
Cauline leaves | 7–17, often concealing stem proximally; blade auricles 2–5 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
2–10(–13), not concealing stem; blade auricles absent or, rarely, to 0.7 mm, surfaces of distalmost leaves glabrous or margins sparsely ciliate. |
Racemes | 19–39-flowered, usually unbranched. |
4–14-flowered, usually 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 usually sparsely pubescent, rarely glabrous; petals whitish to pale lavender, 4–6 × 1–1.5 mm, glabrous; pollen ellipsoid or spheroid. |
Fruiting pedicels | reflexed, recurved proximally, 5–13 mm, glabrous. |
divaricate-ascending to horizontal, curved or angled downward, 3–7(–10) mm, usually glabrous, rarely with some simple trichomes. |
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. |
widely pendent, not appressed to rachis, not secund, curved to nearly straight, edges parallel, 2.2–4 cm × 1.2–2.1 mm; valves glabrous; ovules 40–70(–90) per ovary; style 0.1–0.3(–0.5) mm. |
Seeds | sub-biseriate, 2–2.5 × 1.1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
biseriate, 0.9–1.2 × 0.6–0.9 mm, usually not winged. |
2n | = 14, 21. |
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Boechera tularensis |
Boechera pendulina |
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Phenology | Flowering Jun–Jul. | Flowering Apr–Jun. |
Habitat | Rocky slopes in montane and subalpine habitats | Rock outcrops, open gravelly flats and hillsides in sagebrush, pinyon-juniper, mountain mahogany, open conifer forests |
Elevation | 2400-3200 m (7900-10500 ft) | 1600-3100 m (5200-10200 ft) |
Distribution |
CA |
AZ; CA; CO; NV; UT; WY
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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.) |
Although included in Arabis (Boechera) demissa by some authors (e.g., S. L. Welsh et al. 2003; N. H. Holmgren 2005b), B. pendulina is readily distinguished from that species (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). Typical collections are sexual diploids, whereas the type of var. russeola is a triploid apomict; further study is needed to determine if the two are conspecific. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 410. | FNA vol. 7, p. 395. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis pendulina, Arabis demissa var. russeola, Arabis diehlii, Arabis pendulina var. russeola, Arabis setulosa, B. demissa var. pendulina, B. demissa var. russeola, B. pendulina var. russeola | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 249. (2007) | (Greene) W. A. Weber: Phytologia 51: 370. (1982) |
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