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mountain saxifrage, redwool saxifrage, western saxifrage

Habit Plants in groups or sometimes almost mat-forming, with bulbils on caudices or rhizomatous. Plants solitary or tufted, with bulbils on caudices.
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, 1–10 cm;

blade broadly ovate to elliptic, 2–14 cm, thin to slightly fleshy, base truncate, margins deeply dentate (teeth 2+ mm), sparsely glandular-ciliate, surfaces densely white-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).

15+-flowered, open, lax thyrses, 10–50 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 reflexed, oblong;

petals white, with 2 basal yellow spots (distinct even in dried material), ovate to elliptic, short-clawed, 2–4 mm, much longer than sepals;

filaments elongate, (longer than petals), club-shaped;

pistils distinct almost to base;

ovary superior.

Capsules

greenish or reddish to ± dark purple, folliclelike.

greenish to yellow, folliclelike.

2n

= 20, 38, 40, 56, 58.

Micranthes occidentalis

Micranthes caroliniana

Phenology Flowering spring–summer. Flowering spring.
Habitat Wet, rocky or gravelly slopes, moist to dry alpine meadows, flushes Moist soil at bases of vertical or overhanging rock outcrops, seeps
Elevation 500-4000 m (1600-13100 ft) 500-1200 m (1600-3900 ft)
Distribution
from FNA
AK; ID; MT; NV; OR; SD; WA; WY; AB; BC; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
NC; TN; VA; WV
[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.)

Source FNA vol. 8, p. 62. FNA vol. 8, p. 61.
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. 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. 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 caroliniana
Name authority (S. Watson) Small: in N. L. Britton et al., N. Amer. Fl. 22: 144. 1905 , (A. Gray) Small: in N. L. Britton et al., N. Amer. Fl. 22: 146. (1905)
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