Boechera paddoensis |
Boechera goodrichii |
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Mount Adams rock-cress, Mt. Adams rock-cress |
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Habit | Perennials; long-lived; (cespitose); apomictic; caudex usually woody. | Biennials or perennials; short-lived; apomictic; caudex present or absent. |
Stems | 1–3 per caudex branch, arising from center of rosette near ground surface, or arising laterally proximal to sterile shoots, 1–2.5 dm, glabrous throughout. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 2.6–7.4(–10.2) dm, densely pubescent proximally, trichomes short-stalked, 4–8-rayed, 0.1–0.5 mm, sometimes mixed with 2- or 3-rayed ones, to 1 mm, usually sparsely pubescent distally, rarely glabrous. |
Basal leaves | blade narrowly oblanceolate, 1–3(–6) mm wide, margins usually entire, rarely apically few-toothed, not ciliate, surfaces sparsely pubescent, trichomes short-stalked, 4–8-rayed, 0.08–0.2 mm. |
blade oblanceolate, 3–8(–10) mm wide, margins entire or shallowly dentate, ciliate near petiole base, trichomes (simple), to 1 mm, surfaces moderately to densely pubescent, trichomes short-stalked, 4–8-rayed, 0.15–0.4 mm. |
Cauline leaves | 4–8, not concealing stem; blade auricles 1–2 mm, surfaces of distalmost leaves glabrous. |
22–72, concealing stem proximally; blade auricles 1–4 mm, surfaces of distalmost leaves sparsely pubescent or glabrous. |
Racemes | 5–12(–18)-flowered, usually unbranched. |
25–112-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals glabrous; petals lavender to purple, 4–5.5 × 1–1.5 mm, glabrous; pollen spheroid. |
divaricate-ascending at anthesis; sepals pubescent; petals white to lavender, 6–8 × 1–1.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | usually divaricate-ascending, rarely horizontal, straight, 2–5(–10) mm, glabrous. |
divaricate-descending, straight or gently curved, (10–)15–28 mm, usually sparsely pubescent, rarely glabrous, trichomes appressed, branched. |
Fruits | usually divaricate-ascending, rarely horizontal, not appressed to rachis, secund (often weakly so), straight, edges parallel, 3–5.5 cm × 1.5–2 mm; valves glabrous; ovules 42–54 per ovary; style 0.05–0.1 mm. |
pendent, not appressed to rachis, not secund, straight or gently curved, edges parallel, 4.5–6.5 cm × 1.5–3 mm; valves glabrous; ovules 100–136 per ovary; style to 0.2 mm. |
Seeds | uniseriate, 1.1–1.5 × 0.9–1.3 mm; wing continuous, 0.1–0.3 mm wide. |
biseriate or sub-biseriate, 1–1.4 × 0.9–1 mm; wing continuous, 0.05–0.15 mm. |
Boechera paddoensis |
Boechera goodrichii |
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Phenology | Flowering Jul–Aug. | Flowering Apr–May. |
Habitat | Rocky ridges | Rocky slopes in sagebrush, pinyon-juniper woodlands, oak thickets |
Elevation | 1500-2100 m (4900-6900 ft) | 1300-2300 m (4300-7500 ft) |
Distribution |
OR; WA
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NV; UT |
Discussion | Morphological evidence suggests that Boechera paddoensis is an apomictic species that arose through hybridization between B. lemmonii and B. lyallii (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). Boechera paddoensis is known only from the mountains of central Washington and northeastern Oregon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Morphological evidence suggests that Boechera goodrichii is an apomictic species that arose through hybridization between B. gracilipes and B. retrofracta. Some specimens of it originally were identified as Arabis holboellii var. pinetorum (= B. pinetorum), but they are most similar to B. consanguinea (see M. D. Windham and I. A. Al-Shehbaz 2007, 2007b for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 392. | FNA vol. 7, p. 380. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis lemmonii var. paddoensis | Arabis goodrichii |
Name authority | (Rollins) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 268. (2007) | (S. L. Welsh) N. H. Holmgren: in A. Cronquist et al., Intermount. Fl. 2(B): 364. (2005) |
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