Micranthes idahoensis |
Micranthes fragosa |
|
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Idaho saxifrage |
brittle-leaf saxifrage, Clayton's saxifrage, peak saxifrage |
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Habit | Plants solitary or tufted, with bulbils on caudices. | Plants often mat-forming, long, thin-rhizomatous. |
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 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. |
Inflorescences | 15+-flowered, open thyrses, (flowers ± crowded at tips, becoming more open in fruit), 10–40 cm, purple-tipped stipitate-glandular. |
30+-flowered, (flowers sometimes almost secund), open, lax, conic thyrses with ± open cymules on lateral branches, 20–50 cm, purple-tipped stipitate-glandular. |
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). |
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. |
Capsules | green to reddish purple, folliclelike. |
green or reddish purple, folliclelike. |
2n | = 20. |
= 20, 38. |
Micranthes idahoensis |
Micranthes fragosa |
|
Phenology | Flowering spring–early summer. | Flowering spring–summer. |
Habitat | Open ledges and slopes | Wet, mossy cliffs, unstable slopes, often near watercourses |
Elevation | 500-2500 m (1600-8200 ft) | 100-2600 m (300-8500 ft) |
Distribution |
ID; MT; OR; WA
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ID; OR; WA
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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 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.) |
Source | FNA vol. 8, p. 64. | FNA vol. 8, p. 68. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis | Saxifraga fragosa, Saxifraga claytoniifolia, Saxifraga fragosa subsp. claytoniifolia, Saxifraga integrifolia var. claytoniifolia, Saxifraga nidifica var. claytoniifolia |
Name authority | (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 , | (Suksdorf ex Small) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. (1905) |
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