Micranthes fragosa |
Micranthes razshivinii |
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brittle-leaf saxifrage, Clayton's saxifrage, peak saxifrage |
large-petal saxifrage, razshivin's saxifrage |
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Habit | Plants often mat-forming, long, thin-rhizomatous. | Plants solitary or in clusters, rhizomatous. |
Leaves | basal; petiole flattened, 4–10 cm; blade broadly ovate to deltate, 4–8(–10) cm, fleshy, base attenuate, margins entire or minutely denticulate, ciliate, surfaces glabrate to sparsely hairy. |
basal; petiole ± distinct to indistinct, flattened, (0.3–)0.5–3 cm; blade oblanceolate to narrowly oblanceolate or narrowly spatulate, sometimes ± narrowly obovate, (0.5–)0.9–3.5 cm, ± fleshy, base ± attenuate to cuneate, margins (3–)5–7(–9)-toothed in distal 1/2 (teeth 0.5 mm), sparsely ciliate, surfaces glabrous. |
Inflorescences | 30+-flowered, (flowers sometimes almost secund), open, lax, conic thyrses with ± open cymules on lateral branches, 20–50 cm, purple-tipped stipitate-glandular. |
(2–)4–16-flowered, open, racemiform, sometimes paniculiform thyrses, sometimes solitary flowers, 3–15.5(–17 in fruit) cm, glabrous; (bracts reduced). |
Flowers | sepals spreading to slightly reflexed, ovate to deltate; petals white, not spotted, obovate, clawed, 2–3 mm, longer than sepals; filaments linear, flattened; pistils connate to 1/2 their lengths; ovary 1/2+ inferior, appearing more superior in fruit. |
sepals reflexed, oblong or lanceolate to ovate; petals white to cream, often purplish, not spotted, linear to ± narrowly elliptic, not clawed, 2–4 mm, usually longer to sometimes shorter than sepals; filaments linear, flattened; pistils connate 1/2+ their lengths, (conic); ovary ± 1/2 inferior. |
Capsules | green or reddish purple, folliclelike. |
dark purple-black, valvate. |
2n | = 20, 38. |
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Micranthes fragosa |
Micranthes razshivinii |
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Phenology | Flowering spring–summer. | Flowering summer. |
Habitat | Wet, mossy cliffs, unstable slopes, often near watercourses | Tundra, stream banks, alpine rocky slopes |
Elevation | 100-2600 m [300-8500 ft] | 400-2000 m [1300-6600 ft] |
Distribution |
ID; OR; WA
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AK; NT; YT |
Discussion | Micranthes fragosa is restored to specific status here because a review of its differences with M. nidifica shows it to be more distinctive than previously thought, and for consistency in the application of criteria for species recognition within the rest of the genus. In the southernmost part of its range, M. fragosa converges in appearance with M. californica. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Micranthes razshivinii is found in eastern Alaska (eastern Brooks Range, from Atigun Pass eastward and from Mount McKinley National Park eastward) into Yukon and in the Mackenzie and Richardson mountains in the Northwest Territories. Its leaves are generally narrower than those of M. calycina and the teeth are less numerous. The glabrous inflorescence branches of M. razshivinii readily distinguish it from M. calycina, which has hairy branches. The ranges of the two species may overlap or at least abut in the Atigun Pass area of the Brooks Range, in the Mount McKinley National Park area, and possibly in the Saint Elias Mountains. Hybrids would be very difficult to distinguish from the parents but may occur. They have not been observed in the material examined. Plants of this species sometimes have been misidentified as M. davurica (Willdenow) Small, a species restricted to eastern Siberia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 8, p. 68. | FNA vol. 8, p. 59. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Saxifraga fragosa, Saxifraga claytoniifolia, Saxifraga fragosa subsp. claytoniifolia, Saxifraga integrifolia var. claytoniifolia, Saxifraga nidifica var. claytoniifolia | Saxifraga razshivinii |
Name authority | (Suksdorf ex Small) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. (1905) | (Zhmylev) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1021. (2007) |
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