Micranthes petiolaris |
Micranthes tolmiei |
|
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Michaux's saxifrage |
alpine saxifrage, Tolmie's alpine saxifrage, Tolmie's saxifrage |
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Habit | Plants solitary or tufted, with bulbils on caudices. | Plants mat-forming, (stems trailing, thin, basally slightly woody), with slender, woody caudices. |
Leaves | basal; petiole somewhat flattened, 2–6 cm; blade oblanceolate, 2–12 cm, thin, basecuneate to ± attenuate, margins usually 15+-toothed (teeth large, lobelike), densely long glandular-ciliate, surfaces hairy. |
cauline, proximally crowded; petiole absent; blade elliptic-obovate, 0.8–1.5 cm, fleshy, base cuneate, margins entire, sometimes proximally sparsely long-ciliate, surfaces glabrous. |
Inflorescences | 30+-flowered, very open, lax thyrses, (flowers rarely replaced by bulbils), 10–40 cm, densely tangled, purple-tipped stipitate-glandular; (bracts leaflike, gradually reduced distally). |
2–10-flowered, lax cymes, sometimes solitary flowers, 3–12 cm, glabrous or purplish- or pink-tipped stipitate-glandular; (bracts 1–3, proximal). |
Flowers | slightly bilaterally symmetric; sepals reflexed, oblong to elliptic; petals white, 3 with 2 basal yellow spots, 2 without spots, oblanceolate to spatulate, clawed, 3–4.5 mm, longer than sepals; filaments linear, flattened; pistils connate 1/2+ their lengths; ovary superior. |
sepals erect to spreading, ovate; petals white, not spotted, linear to oblanceolate, 2.5–5 mm, longer than sepals, short- or not clawed; filaments broadly club-shaped (± petaloid); pistils connate to 1/2 their lengths; ovary ± superior (to 1/4 adnate to hypanthium). |
Capsules | green to yellow, sometimes purple tinged, valvate |
green, purple mottled, valvate. |
2n | = 30. |
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Micranthes petiolaris |
Micranthes tolmiei |
|
Phenology | Flowering late spring–early autumn. | Flowering summer. |
Habitat | Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock | Arctic and alpine tundra, fell-fields |
Elevation | 500-2100 m (1600-6900 ft) | 500-4000 m (1600-13100 ft) |
Distribution |
GA; KY; MD; NC; SC; TN; VA; WV
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AK; CA; ID; MT; NV; OR; UT; WA; BC
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Discussion | Micranthes petiolaris (Rafinesque) Brouillet & Gornall is an isonym. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Unlike those of most Micranthes species, the leaves of M. tolmiei are proximally cauline and the ovules have two integuments. The seeds have a loose, winglike testa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 58. | FNA vol. 8, p. 54. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris | Saxifraga tolmiei, Saxifraga tolmiei var. ledifolia |
Name authority | (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 , | (Torrey & A. Gray) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1022. 2007 , |
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