Micranthes nelsoniana |
Micranthes occidentalis |
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dotted saxifrage, heartleaf saxifrage, Nelson's saxifrage, saxifrage |
mountain saxifrage, redwool saxifrage, western saxifrage |
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Habit | Plants solitary or tufted, with bulbils on branched caudices, rhizomatous. | Plants in groups or sometimes almost mat-forming, with bulbils on caudices or rhizomatous. | ||||||||||||||||
Leaves | basal; petiole rounded, 3–30 cm; blade reniform to round, 2–9 cm, thin or slightly fleshy, sometimes thick and fleshy, base cordate, margins deeply crenate, eciliate or sparsely short glandular-ciliate, surfaces glabrous or ± hairy. |
basal; petiole flattened, 1–5 cm; blade ovate to elliptic, 1.5–3.5 cm, ± fleshy, base ± attenuate to ± truncate, margins shallowly, sharply serrate, ciliate, surfaces sparsely tangled, reddish brown-hairy abaxially, glabrous adaxially. |
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Inflorescences | 10+-flowered, ± open, lax to congested, conic, sometimes also glomerate thyrses, 10–35 cm, tangled-hairy (pilose-arachnoid) at least distally, sometimes also purple- or brown-tipped stipitate-glandular. |
usually (10–)30+-flowered, flowers crowded into 1+ glomerules in thyrses with ascending branches, 8–30 cm, purple-tipped stipitate-glandular; (bracts glabrous or marginally glandular-ciliate). |
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Flowers | sepals reflexed, ± ovate; petals white to pinkish, rarely orange-spotted, ovate to oblong, narrowly to broadly clawed, 2.5–4.5 mm, longer than sepals; filaments distinctly club-shaped; pistils connate 1/2–3/4 their lengths; ovary superior (to 1/3 adnate to hypanthium). |
sepals ascending to spreading, sometimes reflexed in fruit, ovate to oblong, (surfaces glabrous); petals white, not spotted (spots rarely present), obovate to almost round, clawed, 2–4 mm, to 1.5 times as long as sepals; filaments linear to very slightly widened near anthers, flattened; pistils distinct almost to base; ovary ± superior. |
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Capsules | green to yellow and purplish tinged to dark purple, valvate. |
greenish or reddish to ± dark purple, folliclelike. |
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2n | = 20, 38, 40, 56, 58. |
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Micranthes nelsoniana |
Micranthes occidentalis |
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Phenology | Flowering spring–summer. | |||||||||||||||||
Habitat | Wet, rocky or gravelly slopes, moist to dry alpine meadows, flushes | |||||||||||||||||
Elevation | 500-4000 m (1600-13100 ft) | |||||||||||||||||
Distribution |
AK; OR; WA; AB; BC; NT; NU; YT; Europe (ne Russia); Asia
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AK; ID; MT; NV; OR; SD; WA; WY; AB; BC; SK
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Discussion | Varieties 6 (5 in the flora). Although sometimes reported for North America, Saxifraga nelsoniana var. aestivalis (Fischer & C. A. Meyer) H. Ohba (S. aestivalis Fischer & C. A. Meyer) is found only in Eurasia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Micranthes occidentalis appears closely related to the little-known M. mexicana (Engler & Irmscher) Brouillet & Gornall from Chihuahua, Mexico. The latter is the only species of the genus that occurs in Mexico and not in the United States. Micranthes occidentalis is disjunct between the northern Rocky Mountains and the Cypress Hills of southeastern Alberta and southwestern Saskatchewan, and the Black Hills of South Dakota. It hybridizes with M. idahoensis where their ranges overlap. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 8, p. 54. | FNA vol. 8, p. 62. | ||||||||||||||||
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes | ||||||||||||||||
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Synonyms | Saxifraga nelsoniana, Saxifraga punctata subsp. nelsoniana, Saxifraga punctata var. nelsoniana | Saxifraga occidentalis, Saxifraga allenii, Saxifraga occidentalis var. allenii, Saxifraga occidentalis var. wallowensis, Saxifraga reflexa subsp. occidentalis, Saxifraga saximontana | ||||||||||||||||
Name authority | (D. Don) Small: in N. L. Britton et al., N. Amer. Fl. 22: 147. 1905 , | (S. Watson) Small: in N. L. Britton et al., N. Amer. Fl. 22: 144. 1905 , | ||||||||||||||||
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