Micranthes petiolaris |
Micranthes rhomboidea |
|
---|---|---|
Michaux's saxifrage |
diamond-leaf saxifrage |
|
Habit | Plants solitary or tufted, with bulbils on caudices. | Plants solitary or tufted, with bulbils on 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. |
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. |
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). |
(5–)10–40-flowered, congested, ± glomerate or capitate thyrses, 4–20 cm, usually densely yellow- to cream-tipped stipitate-glandular. |
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 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. |
Capsules | green to yellow, sometimes purple tinged, valvate |
purple, folliclelike. |
2n | = 20, 38, 40, 56. |
|
Micranthes petiolaris |
Micranthes rhomboidea |
|
Phenology | Flowering late spring–early autumn. | Flowering late spring–summer. |
Habitat | Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock | Subalpine and alpine meadows |
Elevation | 500-2100 m (1600-6900 ft) | 1500-4600 m (4900-15100 ft) |
Distribution |
GA; KY; MD; NC; SC; TN; VA; WV
|
AZ; CO; ID; MT; NM; UT; WY
|
Discussion | Micranthes petiolaris (Rafinesque) Brouillet & Gornall is an isonym. (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.) |
Source | FNA vol. 8, p. 58. | FNA vol. 8, p. 69. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris | Saxifraga rhomboidea, Saxifraga austrina, Saxifraga rhomboidea var. austrina, Saxifraga rhomboidea var. franciscana |
Name authority | (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 , | (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. 1905 , |
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