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Micranthes lyallii

Lyall's saxifrage, red-stem saxifrage

storm saxifrage

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

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.

basal;

petiole indistinct (leaves appearing sessile), flattened, 2–8+ mm;

blade oblanceolate to obovate, 4–10(–30) mm, fleshy, base cuneate to attenuate, margins entire or minutely denticulate, eciliate, (apex acute to obtuse or rounded), surfaces ± glabrous; (venation pinnate or palmate).

Inflorescences

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

5–15(–20)-flowered, congested thyrses, 3–10(–15) cm, glabrous or sparsely purple-tipped stipitate-glandular.

Flowers

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).

sepals spreading, ovate;

petals white, not spotted, linear to obovate, clawed, to 1.5 mm, shorter than sepals;

filaments linear, flattened;

pistils connate to 1/2 their lengths;

ovary inferior.

Capsules

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

reddish purple, valvate.

2n

= ca. 56, 58.

= 10.

Micranthes lyallii

Micranthes tempestiva

Phenology Flowering summer–early autumn. Flowering summer.
Habitat Wet, rocky meadows, mountain to alpine streamsides Rocky ledges, slopes, or snow-bed meadows
Elevation 800-4000 m (2600-13100 ft) 2400-3200 m (7900-10500 ft)
Distribution
from FNA
AK; ID; MT; WA; AB; BC; NT; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
MT
[BONAP county map]
Discussion

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.)

Of conservation concern.

Micranthes tempestiva is known only from the Bitterroot Mountains and Anaconda Range.

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

Source FNA vol. 8, p. 57. FNA vol. 8, p. 69.
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. 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. rhomboidea, M. rufidula, M. spicata, M. stellaris, M. subapetala, M. tenuis, M. texana, M. tischii, M. tolmiei, M. unalaschcensis, M. virginiensis
Synonyms Saxifraga lyallii, Saxifraga lyallii subsp. hultenii, Saxifraga lyallii var. hultenii Saxifraga tempestiva
Name authority (Engler) Small: in N. L. Britton et al., N. Amer. Fl. 22: 143. 1905 , (Elvander & Denton) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1021. 2007 ,
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