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

Micranthes oregana

bog saxifrage, Oregon or bogsaxifrage, Oregon saxifrage

Habit Plants often mat-forming, long, thin-rhizomatous. Plants solitary or in clusters, with caudex or thick, fleshy rhizomes.
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 indistinct, flattened, 3–10 cm;

blade linear to oblanceolate, 6–25 cm, fleshy, base cuneate, margins serrulate to denticulate, ciliate, surfaces glabrous or sparsely hairy.

Inflorescences

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

(30–)50+-flowered, open to ± crowded, conic to cylindric thyrses, 25–125 cm, hairy proximally, yellow- to pink-tipped stipitate-glandular distally.

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 reflexed, ovate to triangular;

petals white, not spotted, broadly elliptic to obovate and 2 times as long as sepals, sometimes oblanceolate and equaling or shorter than sepals, clawed, 2–5 mm;

filaments linear, flattened;

pistils connate to 1/2 their lengths;

ovary 1/2+ inferior, often appearing superior in fruit.

Capsules

green or reddish purple, folliclelike.

green to reddish purple, folliclelike.

2n

= 20, 38.

= 38, 76.

Micranthes fragosa

Micranthes oregana

Phenology Flowering spring–summer. Flowering early spring–summer.
Habitat Wet, mossy cliffs, unstable slopes, often near watercourses Bogs, marshes
Elevation 100-2600 m [300-8500 ft] 100-2500 m [300-8200 ft]
Distribution
from FNA
ID; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; WA; AB
[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.)

In both habitat and morphology, Micranthes oregana is similar to M. pensylvanica. A thorough investigation of the two species, especially the populations in Colorado that are disjunct from those in Montana, is needed to clarify relationships. The name Saxifraga integrifolia was misapplied to M. oregana by early California authors.

(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. 67. 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. 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 fragosa, Saxifraga claytoniifolia, Saxifraga fragosa subsp. claytoniifolia, Saxifraga integrifolia var. claytoniifolia, Saxifraga nidifica var. claytoniifolia Saxifraga oregana, Saxifraga montanensis, Saxifraga oregana var. montanensis
Name authority (Suksdorf ex Small) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. (1905) (Howell) Small: in N. L. Britton et al., N. Amer. Fl. 22: 138. 1905 ,
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