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mountain saxifrage, redwool saxifrage, western saxifrage

brittle-leaf saxifrage, Clayton's saxifrage, peak saxifrage

Habit Plants in groups or sometimes almost mat-forming, with bulbils on caudices or rhizomatous. Plants often mat-forming, long, thin-rhizomatous.
Leaves

basal;

petiole flattened, 1–5 cm;

blade ovate to elliptic, 1.5–3.5 cm, ± fleshy, base ± attenuate to ± truncate, margins shallowly, sharply serrate, ciliate, surfaces sparsely tangled, reddish brown-hairy abaxially, glabrous 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

usually (10–)30+-flowered, flowers crowded into 1+ glomerules in thyrses with ascending branches, 8–30 cm, purple-tipped stipitate-glandular; (bracts glabrous or marginally glandular-ciliate).

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 ascending to spreading, sometimes reflexed in fruit, ovate to oblong, (surfaces glabrous);

petals white, not spotted (spots rarely present), obovate to almost round, clawed, 2–4 mm, to 1.5 times as long as sepals;

filaments linear to very slightly widened near anthers, flattened;

pistils distinct almost to base;

ovary ± superior.

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

greenish or reddish to ± dark purple, folliclelike.

green or reddish purple, folliclelike.

2n

= 20, 38, 40, 56, 58.

= 20, 38.

Micranthes occidentalis

Micranthes fragosa

Phenology Flowering spring–summer. Flowering spring–summer.
Habitat Wet, rocky or gravelly slopes, moist to dry alpine meadows, flushes Wet, mossy cliffs, unstable slopes, often near watercourses
Elevation 500-4000 m (1600-13100 ft) 100-2600 m (300-8500 ft)
Distribution
from FNA
AK; ID; MT; NV; OR; SD; WA; WY; AB; BC; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Micranthes occidentalis appears closely related to the little-known M. mexicana (Engler & Irmscher) Brouillet & Gornall from Chihuahua, Mexico. The latter is the only species of the genus that occurs in Mexico and not in the United States. Micranthes occidentalis is disjunct between the northern Rocky Mountains and the Cypress Hills of southeastern Alberta and southwestern Saskatchewan, and the Black Hills of South Dakota. It hybridizes with M. idahoensis where their ranges overlap.

(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. 62. FNA vol. 8, p. 68.
Parent taxa Saxifragaceae > Micranthes Saxifragaceae > Micranthes
Sibling taxa
M. apetala, M. aprica, M. bryophora, M. californica, M. calycina, M. careyana, M. caroliniana, M. eriophora, M. ferruginea, M. foliolosa, M. fragosa, M. gaspensis, M. gormanii, M. hieraciifolia, M. hitchcockiana, M. howellii, M. idahoensis, M. integrifolia, M. lyallii, M. marshallii, M. micranthidifolia, M. nelsoniana, M. nidifica, M. nivalis, M. nudicaulis, M. odontoloma, M. oregana, M. palmeri, M. pensylvanica, M. petiolaris, M. razshivinii, M. reflexa, M. rhomboidea, M. rufidula, M. spicata, M. stellaris, M. subapetala, M. tempestiva, M. tenuis, M. texana, M. tischii, M. tolmiei, M. unalaschcensis, M. virginiensis
M. apetala, M. aprica, M. bryophora, M. californica, M. calycina, M. careyana, M. caroliniana, M. eriophora, M. ferruginea, M. foliolosa, M. gaspensis, M. gormanii, M. hieraciifolia, M. hitchcockiana, M. howellii, M. idahoensis, M. integrifolia, M. lyallii, M. marshallii, M. micranthidifolia, M. nelsoniana, M. nidifica, M. nivalis, M. nudicaulis, M. occidentalis, M. odontoloma, M. oregana, M. palmeri, M. pensylvanica, M. petiolaris, M. razshivinii, M. reflexa, M. rhomboidea, M. rufidula, M. spicata, M. stellaris, M. subapetala, M. tempestiva, M. tenuis, M. texana, M. tischii, M. tolmiei, M. unalaschcensis, M. virginiensis
Synonyms Saxifraga occidentalis, Saxifraga allenii, Saxifraga occidentalis var. allenii, Saxifraga occidentalis var. wallowensis, Saxifraga reflexa subsp. occidentalis, Saxifraga saximontana Saxifraga fragosa, Saxifraga claytoniifolia, Saxifraga fragosa subsp. claytoniifolia, Saxifraga integrifolia var. claytoniifolia, Saxifraga nidifica var. claytoniifolia
Name authority (S. Watson) Small: in N. L. Britton et al., N. Amer. Fl. 22: 144. 1905 , (Suksdorf ex Small) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. (1905)
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