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bog saxifrage, Oregon or bogsaxifrage, Oregon saxifrage

Michaux's saxifrage

Habit Plants solitary or in clusters, with caudex or thick, fleshy rhizomes. Plants solitary or tufted, with bulbils on caudices.
Leaves

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.

basal;

petiole somewhat flattened, 2–6 cm;

blade oblanceolate, 2–12 cm, thin, basecuneate to ± attenuate, margins usually 15+-toothed (teeth large, lobelike), densely long glandular-ciliate, surfaces hairy.

Inflorescences

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

30+-flowered, very open, lax thyrses, (flowers rarely replaced by bulbils), 10–40 cm, densely tangled, purple-tipped stipitate-glandular; (bracts leaflike, gradually reduced distally).

Flowers

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.

slightly bilaterally symmetric;

sepals reflexed, oblong to elliptic;

petals white, 3 with 2 basal yellow spots, 2 without spots, oblanceolate to spatulate, clawed, 3–4.5 mm, longer than sepals;

filaments linear, flattened;

pistils connate 1/2+ their lengths;

ovary superior.

Capsules

green to reddish purple, folliclelike.

green to yellow, sometimes purple tinged, valvate

2n

= 38, 76.

Micranthes oregana

Micranthes petiolaris

Phenology Flowering early spring–summer. Flowering late spring–early autumn.
Habitat Bogs, marshes Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock
Elevation 100-2500 m (300-8200 ft) 500-2100 m (1600-6900 ft)
Distribution
from FNA
CA; CO; ID; MT; NV; OR; WA; AB
[WildflowerSearch map]
[BONAP county map]
from FNA
GA; KY; MD; NC; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Micranthes petiolaris (Rafinesque) Brouillet & Gornall is an isonym.

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

Source FNA vol. 8, p. 67. FNA vol. 8, p. 58.
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. 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
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. 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 oregana, Saxifraga montanensis, Saxifraga oregana var. montanensis Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris
Name authority (Howell) Small: in N. L. Britton et al., N. Amer. Fl. 22: 138. 1905 , (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 ,
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