Micranthes lyallii |
Micranthes tempestiva |
Micranthes petiolaris |
|
---|---|---|---|
Lyall's saxifrage, red-stem saxifrage |
storm saxifrage |
Michaux's saxifrage |
|
Habit | Plants solitary or sometimes mat-forming, rhizomatous. | Plants solitary or in groups, with bulbils on caudices. | Plants solitary or tufted, with bulbils on caudices. |
Leaves | basal; petiole rounded to flattened, 2–10 cm; blade spatulate to obovate, 0.8–8 cm, thin, base cuneate to slightly attenuate, margins serrate to dentate, eciliate or sparsely glandular-ciliate, surfaces abaxially glabrous, adaxially sparsely brown-hairy. |
basal; petiole indistinct (leaves appearing sessile), flattened, 2–8+ mm; blade oblanceolate to obovate, 4–10(–30) mm, fleshy, base cuneate to attenuate, margins entire or minutely denticulate, eciliate, (apex acute to obtuse or rounded), surfaces ± glabrous; (venation pinnate or palmate). |
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 | usually 10–15-flowered, lax, cylindric thyrses, (red), (4–)7–30 cm, sparsely purple-tipped stipitate-glandular. |
5–15(–20)-flowered, congested thyrses, 3–10(–15) cm, glabrous or sparsely 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, oblong to elliptic; petals white, each with 2 basal yellowish green spots, elliptic to round, clawed, 2–5.5 mm, longer than sepals; filaments club-shaped, (to 6 mm); pistils connate 1/2+ their lengths; ovary superior, (to 1/3 adnate to hypanthium). |
sepals spreading, ovate; petals white, not spotted, linear to obovate, clawed, to 1.5 mm, shorter than sepals; filaments linear, flattened; pistils connate to 1/2 their lengths; ovary inferior. |
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 yellow, distal 1/2 purple, ± folliclelike, (basally connate). |
reddish purple, valvate. |
green to yellow, sometimes purple tinged, valvate |
2n | = ca. 56, 58. |
= 10. |
|
Micranthes lyallii |
Micranthes tempestiva |
Micranthes petiolaris |
|
Phenology | Flowering summer–early autumn. | Flowering summer. | Flowering late spring–early autumn. |
Habitat | Wet, rocky meadows, mountain to alpine streamsides | Rocky ledges, slopes, or snow-bed meadows | Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock |
Elevation | 800-4000 m (2600-13100 ft) | 2400-3200 m (7900-10500 ft) | 500-2100 m (1600-6900 ft) |
Distribution |
AK; ID; MT; WA; AB; BC; NT; YT
|
MT |
GA; KY; MD; NC; SC; TN; VA; WV
|
Discussion | Although they have nearly disjunct sets of populations, the subspecies of Micranthes lyallii are difficult to distinguish from each other. The more northern plants tend to be larger with wider leaves and often have been called Saxifraga lyallii subsp. or var. hultenii. Apparent hybrids with M. odontoloma occur in Alberta, British Columbia, and northern Idaho, and near Glacier National Park, Montana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Micranthes tempestiva is known only from the Bitterroot Mountains and Anaconda Range. (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. 57. | FNA vol. 8, p. 69. | FNA vol. 8, p. 58. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | |||
Synonyms | Saxifraga lyallii, Saxifraga lyallii subsp. hultenii, Saxifraga lyallii var. hultenii | Saxifraga tempestiva | Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris |
Name authority | (Engler) Small: in N. L. Britton et al., N. Amer. Fl. 22: 143. 1905 , | (Elvander & Denton) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1021. 2007 , | (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 , |
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