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

diamond-leaf saxifrage

Habit Plants often mat-forming, long, thin-rhizomatous. Plants solitary or tufted, with bulbils on caudices.
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 flattened, 1–3 cm;

blade broadly ovate to triangular, 1–3 cm, fleshy, base attenuate, margins coarsely serrate, ciliate, surfaces sparsely to moderately tangled, reddish brown-hairy abaxially, glabrous adaxially.

Inflorescences

30+-flowered, (flowers sometimes almost secund), open, lax, conic thyrses with ± open cymules on lateral branches, 20–50 cm, purple-tipped stipitate-glandular.

(5–)10–40-flowered, congested, ± glomerate or capitate thyrses, 4–20 cm, usually densely yellow- to cream-tipped stipitate-glandular.

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 ascending, ovate;

petals white, not spotted, oblong to elliptic, clawed, 2–4 mm, 1.5+ times as long as sepals;

filaments linear, flattened;

pistils connate to 1/2 their lengths;

ovary inferior, appearing more superior in fruit.

Capsules

green or reddish purple, folliclelike.

purple, folliclelike.

2n

= 20, 38.

= 20, 38, 40, 56.

Micranthes fragosa

Micranthes rhomboidea

Phenology Flowering spring–summer. Flowering late spring–summer.
Habitat Wet, mossy cliffs, unstable slopes, often near watercourses Subalpine and alpine meadows
Elevation 100-2600 m [300-8500 ft] 1500-4600 m [4900-15100 ft]
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; ID; MT; NM; UT; WY
[WildflowerSearch map]
[BONAP county map]
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 rhomboidea is somewhat polymorphic; variants have been given taxonomic designations with little consistency. The chromosome number variation needs thorough study, as in other species of Micranthes, because no obvious correlations with morphology or geographic distribution are known (B. L. Bethers 1973). Reports from Canada (Alberta, Saskatchewan) were rejected as misidentifications of M. occidentalis.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 8, p. 68. Treatment authors: Luc Brouillet, Patrick E. Elvander†. FNA vol. 8, p. 69. Treatment authors: Luc Brouillet, Patrick E. Elvander†.
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. 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
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. occidentalis, M. odontoloma, M. oregana, M. palmeri, M. pensylvanica, M. petiolaris, M. razshivinii, M. reflexa, M. rufidula, M. spicata, M. stellaris, M. subapetala, M. tempestiva, M. tenuis, M. texana, M. tischii, M. tolmiei, M. unalaschcensis, M. virginiensis
Synonyms Saxifraga fragosa, Saxifraga claytoniifolia, Saxifraga fragosa subsp. claytoniifolia, Saxifraga integrifolia var. claytoniifolia, Saxifraga nidifica var. claytoniifolia Saxifraga rhomboidea, Saxifraga austrina, Saxifraga rhomboidea var. austrina, Saxifraga rhomboidea var. franciscana
Name authority (Suksdorf ex Small) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. (1905) (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. 1905 ,
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