Boechera paupercula |
Boechera fructicosa |
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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-lived; apomictic; 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. |
3 to many per caudex branch, arising from margin of rosette near ground surface, 3.5–6 dm, pubescent proximally, trichomes short-stalked, 2–4-rayed, 0.2–0.3 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 oblanceolate, 3–7 mm wide, margins dentate, ciliate proximally, trichomes (simple), to 0.3 mm, surfaces pubescent, trichomes short-stalked, 4–8-rayed, 0.05–0.2 mm. |
Cauline leaves | 2–6, rarely concealing stem; blade auricles 0 (or 0.2–1.5) mm, surfaces of distalmost leaves glabrous. |
5–10, not concealing stem; blade auricles 0.5–1 mm, surfaces of distalmost leaves glabrous. |
Racemes | 3–8-flowered, unbranched. |
10–18-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. |
divaricate-ascending at anthesis; sepals pubescent; petals lavender, 4–6 × 1–1.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
divaricate-descending, straight, 5–10 mm, glabrous. |
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-descending, not appressed to rachis, not secund, curved, edges parallel, 4–6 cm × 1.5–1.8 mm; valves glabrous; ovules 60–70 per ovary; style 0.1–0.4 mm. |
Seeds | usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide. |
uniseriate, 1.5–2 × 1–1.3 mm; wing distal, ca. 0.1 mm wide. |
Boechera paupercula |
Boechera fructicosa |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Dry, disturbed soil |
Elevation | 2400-3400 m (7900-11200 ft) | ca. 2000 m (ca. 6600 ft) |
Distribution |
CA; ID; OR; WA; WY
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WY |
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.) |
Boechera fructicosa is known only from the type collection (A. & E. Nelson 5681) taken near Undine Falls in Park County. Multiple plants are represented (comprising the holotype and four isotypes), though one specimen with the same number at RM is B. stricta. Although the exact parentage of this apomictic hybrid remains in doubt, it is virtually certain that B. microphylla contributed at least one genome. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 379. |
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 | Arabis fructicosa |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | (A. Nelson) Al-Shehbaz: Novon 13: 385. (2003) |
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