Micranthes nelsoniana |
Micranthes rhomboidea |
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dotted saxifrage, heartleaf saxifrage, Nelson's saxifrage, saxifrage |
diamond-leaf saxifrage |
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Habit | Plants solitary or tufted, with bulbils on branched caudices, rhizomatous. | Plants solitary or tufted, with bulbils on caudices. | ||||||||||||||||
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, 1–3 cm; blade broadly ovate to triangular, 1–3 cm, fleshy, base attenuate, margins coarsely serrate, ciliate, surfaces sparsely to moderately 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. |
(5–)10–40-flowered, congested, ± glomerate or capitate thyrses, 4–20 cm, usually densely yellow- to cream-tipped stipitate-glandular. |
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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, ovate; petals white, not spotted, oblong to elliptic, clawed, 2–4 mm, 1.5+ times as long as sepals; filaments linear, flattened; pistils connate to 1/2 their lengths; ovary inferior, appearing more superior in fruit. |
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Capsules | green to yellow and purplish tinged to dark purple, valvate. |
purple, folliclelike. |
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2n | = 20, 38, 40, 56. |
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Micranthes nelsoniana |
Micranthes rhomboidea |
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Phenology | Flowering late spring–summer. | |||||||||||||||||
Habitat | Subalpine and alpine meadows | |||||||||||||||||
Elevation | 1500-4600 m (4900-15100 ft) | |||||||||||||||||
Distribution |
AK; OR; WA; AB; BC; NT; NU; YT; Europe (ne Russia); Asia
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AZ; CO; ID; MT; NM; UT; WY
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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 rhomboidea is somewhat polymorphic; variants have been given taxonomic designations with little consistency. The chromosome number variation needs thorough study, as in other species of Micranthes, because no obvious correlations with morphology or geographic distribution are known (B. L. Bethers 1973). Reports from Canada (Alberta, Saskatchewan) were rejected as misidentifications of M. occidentalis. (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. 69. | ||||||||||||||||
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Saxifraga nelsoniana, Saxifraga punctata subsp. nelsoniana, Saxifraga punctata var. nelsoniana | Saxifraga rhomboidea, Saxifraga austrina, Saxifraga rhomboidea var. austrina, Saxifraga rhomboidea var. franciscana | ||||||||||||||||
Name authority | (D. Don) Small: in N. L. Britton et al., N. Amer. Fl. 22: 147. 1905 , | (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. 1905 , | ||||||||||||||||
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