Boechera howellii |
Boechera bodiensis |
|
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Howell's flat-seed rock-cress, Howell's rockcress, pioneer rock-cress |
Bodie Hills rock cress |
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Habit | Perennials; long-lived; sexual; caudex usually woody. | Perennials; long-lived; (cespitose); apomictic; caudex somewhat woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 0.6–2(–3) dm, glabrous throughout. |
usually 1 per caudex branch, arising from center of rosette near ground surface, 1.5–3.5 dm, densely pubescent proximally, trichomes short-stalked, 5–10-rayed, to 0.7 mm, sparsely pubescent or glabrous distally. |
Basal leaves | blade narrowly oblanceolate, 1–7 mm wide, margins entire, ciliate proximally, trichomes (simple mixed with a few short-stalked, 2-rayed ones) 0.1–0.4 mm, surfaces glabrous. |
blade narrowly oblanceolate, 1–3 mm wide, margins entire, ciliate proximally, trichomes to 0.7 mm, surfaces densely pubescent, trichomes short-stalked, 5–10-rayed, 0.08–0.25 mm. |
Cauline leaves | 2–4, not concealing stem; blade auricles (0–)0.2–1 mm, surfaces of distalmost leaves usually glabrous, rarely ciliate proximally. |
4–9, not concealing stem; blade auricles 0.5–2 mm, surfaces of distalmost leaves pubescent. |
Racemes | 2–5-flowered, unbranched. |
8–25-flowered, usually unbranched. |
Flowers | erect to ascending at anthesis; sepals glabrous; petals white to dark lavender, 4–8 × 1–2.5 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals lavender to purple, 4–5 × ca. 1 mm, glabrous; pollen spheroid. |
Fruiting pedicels | ascending, straight, 4–10 mm, glabrous. |
ascending to divaricate-ascending, straight, 3–7 mm, pubescent, trichomes appressed, branched. |
Fruits | suberect to ascending, usually not appressed to rachis, not secund, straight to curved, edges often somewhat undulate (not parallel), 2.5–6.5 cm × 3–7 mm; valves glabrous; ovules 10–20 per ovary; style 0.05–0.3 mm. |
divaricate-ascending, not appressed to rachis, not secund, straight or curved, edges parallel, 4–6.2 cm × 1.2–1.8 mm; valves glabrous; ovules 48–68 per ovary; style 0.1–0.2 mm. |
Seeds | uniseriate, 3–6 × 2–4 mm; wing continuous, 1.3–2.5 mm wide. |
uniseriate, 1–1.5 × 0.8–1.2 mm; wing continuous, 0.1–0.15 mm wide. |
Boechera howellii |
Boechera bodiensis |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Rock outcrops, talus slopes and gravelly soil in alpine and subalpine habitats | Loose soil, crevices of igneous rock |
Elevation | 1800-3800 m (5900-12500 ft) | 2400-2900 m (7900-9500 ft) |
Distribution |
CA; NV; OR
|
CA; NV |
Discussion | Boechera howellii usually is subsumed under B. platysperma, but the two taxa are distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. In his original description, Rollins suggested that Boechera bodiensis is closely related to B. cobrensis and B. falcifructa. Subsequent studies (M. D. Windham and I. A. Al-Shehbaz, unpubl.) indicate that both B. bodiensis and B. falcifructa are apomictic hybrids containing one or more genomes derived from B. cobrensis. In the case of B. falcifructa, the second parent is clearly B. fernaldiana, but the second parent of B. bodiensis remains uncertain. Boechera bodiensis is most similar to B. falcifructa. The latter differs by having gently recurved fruiting pedicels 6–12 mm, 62–80 ovules per ovary, and pendulous fruits; it is known from Elko and Lander counties, Nevada. By contrast, B. bodiensis has straight fruiting pedicels 3–7 mm long, divaricate-ascending fruits, 48–68 ovules per ovary, and is known from Mono County, California, and Lyon and Mineral counties, Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 384. | FNA vol. 7, p. 367. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis howellii, Arabis conferta, Arabis inamoena var. acutata, Arabis platyloba, Arabis platysperma var. howellii, Arabis platysperma var. imparata | Arabis bodiensis |
Name authority | (S. Watson) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 69. (2006) | (Rollins) Al-Shehbaz: Novon 13: 384. (2003) |
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