Boechera harrisonii |
Boechera xylopoda |
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beautiful rockcress, bigfoot hybrid rockcress |
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Habit | Perennials; long-lived; (some-what cespitose); apomictic; caudex often woody. | Perennials; long-lived; apomictic; caudex woody. |
Stems | usually 3–7 per caudex branch, arising from margin of rosette near ground surface, 0.5–2.5 dm, usually sparsely pubescent proximally, rarely glabrous, trichomes short-stalked, 2- or 3-rayed, 0.06–0.2 mm, glabrous distally. |
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 narrowly oblanceolate, 2–4 mm wide, margins entire or somewhat dentate, ciliate near petiole base, trichomes (simple), to 0.5 mm, surfaces sparsely pubescent, trichomes short-stalked, 2–5-rayed, 0.1–0.25 mm. |
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 | 3–7, not concealing stem; blade auricles 0.5–1.5 mm, surfaces of distalmost leaves glabrous. |
8–18, usually not concealing stem; blade auricles 1–2 mm, surfaces of distalmost leaves sparsely pubescent. |
Racemes | 5–12-flowered, usually unbranched. |
20–38-flowered, usually unbranched. |
Flowers | ascending at anthesis; sepals pubescent; petals lavender, 5–7.5 × 0.8–1.5 mm, glabrous; pollen spheroid. |
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 | divaricate-ascending, straight, 8–12 mm, glabrous. |
descending-divaricate, usually recurved, 9–20 mm, usually pubescent, rarely glabrous, trichomes subappressed, branched. |
Fruits | usually divaricate-ascending, rarely nearly horizontal, not appressed to rachis, not secund, curved to straight, edges parallel, 3–4.7 cm × 1–1.5 mm; valves glabrous; ovules 64–86 per ovary; style 0.2–0.5 mm. |
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 | uniseriate, 1.1–1.3 × 0.8–1.1 mm; wing continuous, 0.08–0.1 mm wide. |
sub-biseriate, 2–2.5 × 1.3–1.6 mm; wing continuous, 0.2–0.25 mm wide. |
Boechera harrisonii |
Boechera xylopoda |
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Phenology | Flowering May–Jun. | Flowering Mar–May. |
Habitat | Limestone and quartzite cliffs | Rock outcrops and gravelly slopes, often under shelter of shrubs in desert scrub, sagebrush, and chaparral communities |
Elevation | 1500-1600 m (4900-5200 ft) | 900-2000 m (3000-6600 ft) |
Distribution |
UT |
CA; NV
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Discussion | Morphological evidence suggests that Boechera harrisonii is an apomictic species that arose through hybridization between B. microphylla and B. perennans (see M. D. Windham and I. A. Al-Shehbaz 2007 for detailed comparison). Boechera harrisonii is known only from Utah and Wasatch counties in north-central Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 383. | FNA vol. 7, p. 411. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Arabis harrisonii, B. microphylla var. harrisonii | Arabis pulchra var. gracilis, Arabis pulchra var. glabrescens, Arabis pulchra var. viridis, B. pulchra var. gracilis |
Name authority | (S. L. Welsh) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 266. (2007) | Windham & Al-Shehbaz: Harvard Pap. Bot. 12: 250. (2007) |
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