Boechera paupercula |
Boechera glareosa |
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boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress |
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Habit | Perennials; long-lived; (cespitose); sexual; caudex often woody. | Perennials; short- to long-lived; sexual; caudex usually not woody. |
Stems | usually 1 per caudex branch, arising from center of rosette near ground surface, 0.3–1.5 dm, densely pubescent proximally, trichomes simple and short-stalked, 2–4-rayed, (0.07–)0.1–0.2 mm, glabrous or sparsely pubescent distally. |
usually 2–6 per caudex branch, arising from margin of rosette near ground surface, 0.8–4 dm, densely pubescent proximally, trichomes simple and short-stalked, 2-rayed, 0.3–0.6 mm, glabrous distally. |
Basal leaves | blade linear-oblanceolate, 1–3(–5) mm wide, margins entire, ciliate proximally, trichomes to 0.4 mm, surfaces densely pubescent, trichomes short-stalked, 2–6-rayed, (0.07–)0.1–0.2 mm. |
blade narrowly oblanceolate, 1–5 mm wide, margins entire or few-toothed, ciliate proximally, trichomes (simple), to 0.9 mm, surfaces densely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.3–0.5 mm. |
Cauline leaves | 2–6, rarely concealing stem; blade auricles 0 (or 0.2–1.5) mm, surfaces of distalmost leaves glabrous. |
3–6, not concealing stem; blade auricles 0.3–0.6 mm, surfaces of distalmost leaves glabrous. |
Racemes | 3–8-flowered, unbranched. |
7–15-flowered, usually unbranched. |
Flowers | erect at anthesis; sepals glabrous or sparsely pubescent; petals lavender to purplish, 4–6(–7) × 1–2 mm, glabrous; pollen ellipsoid. |
ascending at anthesis; sepals pubescent; petals lavender, 3.5–6 × 1–1.5 mm, glabrous; pollen ellipsoid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
divaricate-ascending to horizontal, straight or gently recurved, 4–10 mm, glabrous or sparsely pubescent, trichomes spreading. |
Fruits | erect, appressed to rachis, not secund, straight, edges parallel, 2.5–5.5 cm × 1.3–1.7(–2) mm; valves glabrous; ovules 24–40 per ovary; style 0.2–1 mm. |
divaricate-ascending to horizontal, not appressed to rachis, not secund, usually curved or straight, edges parallel, 2.5–4 cm × 1.2–1.5 mm; valves glabrous; ovules 50–80 per ovary; style 0.05–0.3 mm. |
Seeds | usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide. |
uniseriate, 1–1.5 × 0.7–1 mm; wing usually distal, ca. 0.1 mm wide. |
Boechera paupercula |
Boechera glareosa |
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Phenology | Flowering Jun–Aug. | Flowering May–Jun. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Conglomerate and limestone outcrops in pinyon-juniper and mountain shrub-conifer communities |
Elevation | 2400-3400 m (7900-11200 ft) | 2000-2600 m (6600-8500 ft) |
Distribution |
CA; ID; OR; WA; WY
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CO; UT |
Discussion | Boechera paupercula is usually subsumed under Arabis (Boechera) lyallii but is amply distinct (see M. D. Windham and I. A. Al-Shehbaz 2006 for detailed comparison). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Specimens of Boechera glareosa originally were identified as Arabis microphylla var. macounii (= B. macounii) by R. C. Rollins. The former (a sexual species) is distinguished from the latter (an apomictic hybrid) by having wider (1–2 versus 0.5–0.8 mm) petals, fewer (2–9 versus mostly 9–16) cauline leaves, and fewer (7–15 versus 10–33) flowers per inflorescence. Boechera glareosa is known only from Moffat County, Colorado, and Summit and Uintah counties, Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 380. |
Parent taxa | Brassicaceae > tribe Boechereae > Boechera | Brassicaceae > tribe Boechereae > Boechera |
Sibling taxa | ||
Synonyms | Arabis paupercula, Arabis lyallii var. nubigena, Arabis microphylla var. nubigena, Arabis nubigena | |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | Dorn: Brittonia 55: 1, fig. 1. (2003) |
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