Boechera tularensis |
Boechera lemmonii |
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Tulare rockcress |
Lemmon's rock-cress, Lemmon's suncress, wind-blown suncress |
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Habit | Biennials or perennials; short-lived; apomictic; caudex present or absent. | Perennials; long-lived; (somewhat cespitose); sexual or apomictic; 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 near ground surface, or arising laterally proximal to sterile shoots, 0.5–2(–2.5) dm, glabrous or sparsely pubescent proximally, trichomes short-stalked, 2–6-rayed, 0.1–0.2 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, 1.5–5 mm wide, margins usually entire, rarely slightly dentate, ciliate along petiole, surfaces densely to sparsely pubescent, trichomes short-stalked, 3–9-rayed, 0.1–0.2 mm. |
Cauline leaves | 7–17, often concealing stem proximally; blade auricles 2–5 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
2–8(–12), not concealing stem; blade auricles absent or 0.1–0.5 mm, surfaces of distalmost leaves glabrous or sparsely pubescent. |
Racemes | 19–39-flowered, usually unbranched. |
3–12(–17)-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 glabrous or sparsely pubescent; petals purple to lavender, 3.5–6 × 1–1.5 mm; pollen ellipsoid or spheroid. |
Fruiting pedicels | reflexed, recurved proximally, 5–13 mm, glabrous. |
divaricate-ascending to slightly descending, usually slightly recurved, rarely straight, 2–6 mm, glabrous or sparsely pubescent, trichomes appressed, branched. |
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. |
divaricate-ascending to slightly descending, not appressed to rachis, secund, straight or curved, edges parallel, (1.6–) 2–4.4 cm × 1.6–2.3 mm; valves glabrous; ovules 28 40(–44) per ovary; style 0.1–0.2 mm. |
Seeds | sub-biseriate, 2–2.5 × 1.1–1.5 mm; wing continuous, 0.15–0.25 mm wide. |
uniseriate, 1.3–2 × 1–1.5 mm; wing continuous, 0.1–0.5 mm wide. |
2n | = 14. |
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Boechera tularensis |
Boechera lemmonii |
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Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Rocky slopes in montane and subalpine habitats | Cliffs, talus slopes, and gravelly soil in alpine and subalpine habitats |
Elevation | 2400-3200 m (7900-10500 ft) | 2100-4400 m (6900-14400 ft) |
Distribution |
CA |
AK; CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC; YT
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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.) |
Boechera lemmonii is easily recognized by its combination of secund fruits, mat-forming habit, purplish sepals, and obovate-oblanceolate cauline leaves. Both sexual and apomictic collections are known; further study is needed to determine whether they truly are conspecific. The taxa traditionally treated as Arabis (Boechera) lemmonii vars. depauperata, drepanoloba, and paddoensis are apomictic hybrids here recognized as distinct species (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 410. | FNA vol. 7, p. 388. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis lemmonii, Arabis bracteolata, Arabis canescens var. latifolia, Arabis codyi, Arabis egglestonii, Arabis kennedyi, Arabis latifolia, Arabis oreocallis, Arabis polyclada, Arabis semisepulta | |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 249. (2007) | (S. Watson) W. A. Weber: Phytologia 51: 370. (1982) |
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