Boechera xylopoda |
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beautiful rockcress, bigfoot hybrid rockcress |
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Habit | Perennials; long-lived; apomictic; caudex woody. |
Stems | usually 1 from per caudex branch, arising from center of leaf tuft, elevated above ground surface on woody base, (3–)5–7.5 dm, pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.25–0.9 mm., similarly pubescent distally. |
Basal leaves | blade linear-oblanceolate to oblanceolate, 3–7 mm wide, margins entire or somewhat dentate, ciliate near petiole base, trichomes (simple), to 1.5 mm, surfaces densely pubescent, trichomes short-stalked, 4–8-rayed, 0.15–0.5 mm. |
Cauline leaves | 8–18, usually not concealing stem; blade auricles 1–2 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 20–38-flowered, usually unbranched. |
Flowers | divaricate to pendent at anthesis; sepals pubescent; petals purple, 9–12 × 2–3.5 mm, sparsely pubescent (often some trichomes abaxially); pollen spheroid. |
Fruiting pedicels | descending-divaricate, usually recurved, 9–20 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
Fruits | reflexed, not appressed to rachis, not secund, straight, edges parallel, 5–7 cm × 2–2.5 mm; valves glabrous proximally, sparsely pubescent distally; ovules 98–126 per ovary; style 0.1–0.5 mm. |
Seeds | sub-biseriate, 2–2.5 × 1.3–1.6 mm; wing continuous, 0.2–0.25 mm wide. |
Boechera xylopoda |
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Phenology | Flowering Mar–May. |
Habitat | Rock outcrops and gravelly slopes, often under shelter of shrubs in desert scrub, sagebrush, and chaparral communities |
Elevation | 900-2000 m (3000-6600 ft) |
Distribution |
CA; NV
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Discussion | Although usually treated as a variety of Arabis (Boechera) pulchra, B. xylopoda is an apomictic taxon that is morphologically intermediate between B. perennans and B. pulchra (see M. D. Windham and I. A. Al-Shehbaz 2007b for detailed comparison) and probably arose through hybridization between those two sexual diploids. Arabis trichopoda Greene (1908), not Turczaninow (1840) is an illegitimate name, sometimes found in synonymy with Boechera xylopoda. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 411. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | |
Synonyms | Arabis pulchra var. gracilis, Arabis pulchra var. glabrescens, Arabis pulchra var. viridis, B. pulchra var. gracilis |
Name authority | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 250. (2007) |
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