Micranthes howellii |
Micranthes idahoensis |
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Howell's saxifrage |
Idaho saxifrage |
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Habit | Plants solitary or in groups, with bulbils on caudices. | Plants solitary or tufted, with bulbils on caudices. |
Leaves | basal; petiole flattened, 1–4 cm; blade oblong to narrowly ovate, 1–2(–3) cm, ± fleshy, base attenuate, margins sharply serrate, eciliate, surfaces sparsely tangled, reddish brown-hairy abaxially, glabrous adaxially. |
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. |
Inflorescences | 5–10(–20)-flowered, very open, lax, ± flat-topped cymes or thyrses, 5–10(–20) cm, glabrate to sparsely purple-tipped stipitate-glandular; (bracts glabrous). |
15+-flowered, open thyrses, (flowers ± crowded at tips, becoming more open in fruit), 10–40 cm, purple-tipped stipitate-glandular. |
Flowers | sepals strongly reflexed, elliptic, (surfaces glabrous); petals white, not spotted, obovate to elliptic, clawed, 2.5–4.5 mm, longer than sepals; filaments linear, flattened; pistils distinct almost to base; ovary ± superior. |
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). |
Capsules | purple, valvate. |
green to reddish purple, folliclelike. |
2n | = 20. |
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Micranthes howellii |
Micranthes idahoensis |
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Phenology | Flowering early spring–early summer. | Flowering spring–early summer. |
Habitat | Wet, rocky ledges and crevices | Open ledges and slopes |
Elevation | 0-900 m (0-3000 ft) | 500-2500 m (1600-8200 ft) |
Distribution |
CA; OR
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ID; MT; 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.) |
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Source | FNA vol. 8, p. 63. | FNA vol. 8, p. 64. |
Parent taxa | Saxifragaceae > Micranthes | Saxifragaceae > Micranthes |
Sibling taxa | ||
Synonyms | Saxifraga howellii | Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis |
Name authority | (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 140. (1905) | (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 , |
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