Boechera paupercula |
Boechera pinzliae |
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boechera paupercula, littleleaf rockcress, small-flower rock-cress, tiny suncress |
Pinzl's Rock cress |
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Habit | Perennials; long-lived; (cespitose); sexual; caudex often woody. | Perennials; long-lived; apomictic; caudex usually 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. |
1–3 per caudex branch, arising from margin of rosette near ground surface, 0.4–1.6 dm, densely pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.05–0.2 mm, glabrous or sparsely pubescent 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. |
(petiole glabrous); blade linear-oblanceolate, 1–3 mm wide, margins entire, rarely ciliate proximally, trichomes to 0.5 mm, surfaces densely pubescent, trichomes short-stalked, 2–5-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. |
3–6, not concealing stem; blade auricles 0(–0.3) mm, surfaces of distalmost leaves sparsely to moderately pubescent. |
Racemes | 3–8-flowered, unbranched. |
5–8-flowered, 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 purple, 4–5 × 1–1.5 mm, glabrous; pollen spheroid. |
Fruiting pedicels | erect, straight, 3–9 mm, glabrous or sparsely pubescent. |
ascending to divaricate-ascending, straight, 2–6 mm, glabrous or sparsely pubescent, trichomes appressed, branched. |
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. |
ascending to divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 2.5–4.8 cm × 2.5–3.2 mm; valves glabrous; ovules 26–34 per ovary; style 0.1–0.3 mm. |
Seeds | usually uniseriate, rarely sub-biseriate, 1.5–2(–2.5) × 1–1.4 mm; wing continuous, 0.3–1 mm wide. |
uniseriate, 2.5–3.5 × 1.5–2.5 mm; wing continuous, 0.2–0.9 mm wide. |
Boechera paupercula |
Boechera pinzliae |
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Phenology | Flowering Jun–Aug. | Flowering Jul. |
Habitat | Rock outcrops, talus slopes, gravelly soil in alpine and subalpine habitats | Gravelly granitic soils in alpine and subalpine areas |
Elevation | 2400-3400 m (7900-11200 ft) | 3000-3400 m (9800-11200 ft) |
Distribution |
CA; ID; OR; WA; WY
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CA; NV |
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.) |
Of conservation concern. Morphological evidence suggests that Boechera pinzliae is an apomictic hybrid that contains at least one genome derived from B. platysperma; the other parent has not yet been determined. It is most similar to B. elkoensis, from which it differs in having sparsely pubescent (versus glabrous) sepals and basal leaves with stalked (versus sessile or subsessile) trichomes. Boechera pinzliae is known only from the White Mountains in extreme western Nevada (Esmeralda County) and east-central California (Mono County). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 394. | FNA vol. 7, p. 397. |
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 pinzliae |
Name authority | (Greene) Windham & Al-Shehbaz: Harvard Pap. Bot. 11: 75. (2006) | (Rollins) Al-Shehbaz: Novon 13: 388. (2003) |
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