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Michaux's saxifrage

Micranthes lyallii

Lyall's saxifrage, red-stem saxifrage

Habit Plants solitary or tufted, with bulbils on caudices. Plants solitary or sometimes mat-forming, rhizomatous.
Leaves

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.

basal;

petiole rounded to flattened, 2–10 cm;

blade spatulate to obovate, 0.8–8 cm, thin, base cuneate to slightly attenuate, margins serrate to dentate, eciliate or sparsely glandular-ciliate, surfaces abaxially glabrous, adaxially sparsely brown-hairy.

Inflorescences

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).

usually 10–15-flowered, lax, cylindric thyrses, (red), (4–)7–30 cm, sparsely purple-tipped stipitate-glandular.

Flowers

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.

sepals reflexed, oblong to elliptic;

petals white, each with 2 basal yellowish green spots, elliptic to round, clawed, 2–5.5 mm, longer than sepals;

filaments club-shaped, (to 6 mm);

pistils connate 1/2+ their lengths;

ovary superior, (to 1/3 adnate to hypanthium).

Capsules

green to yellow, sometimes purple tinged, valvate

green to yellow, distal 1/2 purple, ± folliclelike, (basally connate).

2n

= ca. 56, 58.

Micranthes petiolaris

Micranthes lyallii

Phenology Flowering late spring–early autumn. Flowering summer–early autumn.
Habitat Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock Wet, rocky meadows, mountain to alpine streamsides
Elevation 500-2100 m (1600-6900 ft) 800-4000 m (2600-13100 ft)
Distribution
from FNA
GA; KY; MD; NC; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; ID; MT; WA; AB; BC; NT; YT
[WildflowerSearch map]
[BONAP county map]
Discussion

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

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

Although they have nearly disjunct sets of populations, the subspecies of Micranthes lyallii are difficult to distinguish from each other. The more northern plants tend to be larger with wider leaves and often have been called Saxifraga lyallii subsp. or var. hultenii. Apparent hybrids with M. odontoloma occur in Alberta, British Columbia, and northern Idaho, and near Glacier National Park, Montana.

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

Source FNA vol. 8, p. 58. FNA vol. 8, p. 57.
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. 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
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. 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 Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris Saxifraga lyallii, Saxifraga lyallii subsp. hultenii, Saxifraga lyallii var. hultenii
Name authority (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 , (Engler) Small: in N. L. Britton et al., N. Amer. Fl. 22: 143. 1905 ,
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