Micranthes apetala |
Micranthes tenuis |
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tiny swamp saxifrage, western swamp saxifrage |
slender saxifrage |
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Habit | Plants solitary or in clusters, with bulbils on caudices, or short-rhizomatous. | Plants tufted, with bulbils on caudices. |
Leaves | basal; petiole flattened, 0.5–3 cm; blade ± ovate, 2–5 cm, ± fleshy, base attenuate, margins entire or crenulate, eciliate, surfaces hairy. |
basal; petiole broad, flattened, 0.2–1 cm; blade ± obovate to ± obtrullate, 0.5–1.5 cm, ± coriaceous, base ± attenuate to ± cuneate, margins serrate to dentate on distal 1/3–2/3, sometimes ciliate, surfaces glabrous or glabrate abaxially (rarely sparsely reddish brown-hairy). |
Inflorescences | 10–25-flowered, congested, glomerate thyrses, 4–15 cm, pink- to purple-tipped stipitate-glandular (hairs uniseriate). |
usually 2–10-flowered, ± capitate cymes, sometimes solitary flowers, (1–)2–7(–11) cm, hairy or glabrous proximally, glabrate or ± purple-tipped stipitate-glandular distally. (Pedicels proximal ± elongate.) Flowers: sepals erect, ovate to deltate; petals white with purple margins, usually pink or purple tinged, not spotted, obovate to oblong, clawed, 2–3 mm, usually slightly longer than sepals; filaments linear, flattened; pistils connate to 1/2 their lengths; ovary 1/2 inferior, appearing more superior in fruit. |
Flowers | sepals erect to ascending, ovate; petals absent, sometimes 1–5, white to greenish white, not spotted, linear to oblong, clawed, 1–2 mm, much shorter than sepals; filaments linear, flattened; pistils connate to 1/2 their lengths; ovary 1/2+ inferior. |
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Capsules | reddish or purplish, folliclelike. |
reddish to purplish, folliclelike. |
2n | = 38. |
= 20. |
Micranthes apetala |
Micranthes tenuis |
|
Phenology | Flowering early spring–summer. | Flowering summer. |
Habitat | Vernally moist meadows, wet depressions on mountain slopes | Open, mossy tundra, rocky ridges, shady ledges |
Elevation | 600-2800 m (2000-9200 ft) | 0-1500 m (0-4900 ft) |
Distribution |
ID; MT; OR; WA
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AK; BC; LB; NT; NU; QC; YT; Greenland; Europe; Asia (Siberia) |
Discussion | Micranthes tenuis is morphologically distinguished from M. nivalis only with great difficulty. D. A. Webb and R. J. Gornall (1989) claimed that chromosome number is one of the chief reasons for continuing to recognize the species and, indeed, their enumeration of morphologic differences is not entirely convincing. Occasionally, both species appear to occur in the same populations. The generally smaller size, tendency to glabrousness, fewer number of flowers, and petal color variations reasonably distinguish M. tenuis. Depauperate specimens of M. nivalis are particularly difficult to separate from M. tenuis except for their very consistent hairiness and white petals. Due to the morphologic confusion, exact distributions are difficult to assess and chromosome number reports may be doubtful (D. L. Krause and K. I. Beamish 1973). A thorough systematic study is needed. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 8, p. 68. | FNA vol. 8, p. 65. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Saxifraga apetala, Saxifraga integrifolia var. apetala | Saxifraga nivalis var. tenuis, Saxifraga tenuis |
Name authority | (Piper) Small: in N. L. Britton et al., N. Amer. Fl. 22: 135. 1905 , | (Wahlenberg) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. (1905) |
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