Micranthes idahoensis |
Micranthes petiolaris |
|
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Idaho saxifrage |
Michaux's saxifrage |
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Habit | Plants solitary or tufted, with bulbils on caudices. | Plants solitary or tufted, with bulbils on caudices. |
Leaves | basal; petiole flattened, 1–5 cm; blade ovate to elliptic, 1–4 cm, ± fleshy, base attenuate, margins shallowly serrate to dentate (teeth usually to 1 mm), sparsely ciliate, surfaces tangled, reddish brown-hairy abaxially, glabrate adaxially. |
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. |
Inflorescences | 15+-flowered, open thyrses, (flowers ± crowded at tips, becoming more open in fruit), 10–40 cm, purple-tipped stipitate-glandular. |
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). |
Flowers | sepals reflexed, ovate to oblong; petals white, with 2 basal yellow spots (often faded when dried), elliptic to ovate, clawed to nearly not clawed, 1–3.5 mm, ± equaling sepals; filaments club-shaped, not petaloid, (equaling petals); pistils distinct almost to base; ovary superior, (to 1/3 adnate to hypanthium). |
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. |
Capsules | green to reddish purple, folliclelike. |
green to yellow, sometimes purple tinged, valvate |
2n | = 20. |
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Micranthes idahoensis |
Micranthes petiolaris |
|
Phenology | Flowering spring–early summer. | Flowering late spring–early autumn. |
Habitat | Open ledges and slopes | Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock |
Elevation | 500-2500 m (1600-8200 ft) | 500-2100 m (1600-6900 ft) |
Distribution |
ID; MT; OR; WA
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GA; KY; MD; NC; SC; TN; VA; WV
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Discussion | Micranthes idahoensis appears to hybridize with M. occidentalis where their ranges overlap. Intermediates are abundant in some populations along the Idaho-Montana border and in Montana. This phenomenon may explain the range of filament shapes found in M. occidentalis, from flattened to sightly club-shaped. The issue of the status of M. idahoensis with respect to M. marshallii (D. L. Krause and K. I. Beamish 1972) is best deferred until a thorough study of the whole complex over its entire range is done. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Micranthes petiolaris (Rafinesque) Brouillet & Gornall is an isonym. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 64. | FNA vol. 8, p. 58. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis | Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris |
Name authority | (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 , | (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 , |
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