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Lyall's saxifrage, red-stem saxifrage

brook saxifrage, stream saxifrage, streambank saxifrage

Idaho saxifrage

Habit Plants solitary or sometimes mat-forming, rhizomatous. Plants solitary or sometimes grouped, rhizomatous. Plants solitary or tufted, 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 rounded, 2–30 cm;

blade round, 7–40 cm, thin to slightly fleshy, base cordate to truncate, margins regularly dentate, eciliate, surfaces sparsely brownish hairy abaxially, glabrous adaxially.

basal;

petiole flattened, 1–5 cm;

blade ovate to elliptic, 1–4 cm, ± fleshy, base attenuate, margins shallowly serrate to dentate (teeth usually to 1 mm), sparsely ciliate, surfaces tangled, reddish brown-hairy abaxially, glabrate adaxially.

Inflorescences

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

10–30+-flowered, open, lax, flat-topped thyrses, 20–65(–85) cm, glabrous proximally, purple-tipped subsessile-glandular distally.

15+-flowered, open thyrses, (flowers ± crowded at tips, becoming more open in fruit), 10–40 cm, 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 reflexed, ovate to elliptic;

petals white, each with 2 basal yellow spots, round to broadly elliptic, clawed, 3–4.5 mm, longer than sepals;

filaments strongly club-shaped, (to 6 mm);

pistils connate ca. 1/2 their lengths;

ovary superior.

sepals reflexed, ovate to oblong;

petals white, with 2 basal yellow spots (often faded when dried), elliptic to ovate, clawed to nearly not clawed, 1–3.5 mm, ± equaling sepals;

filaments club-shaped, not petaloid, (equaling petals);

pistils distinct almost to base;

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

Capsules

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

green to purple, ± folliclelike.

green to reddish purple, folliclelike.

2n

= ca. 56, 58.

= 24, 48.

= 20.

Micranthes lyallii

Micranthes odontoloma

Micranthes idahoensis

Phenology Flowering summer–early autumn. Flowering summer–early autumn. Flowering spring–early summer.
Habitat Wet, rocky meadows, mountain to alpine streamsides Wet meadows and stream banks Open ledges and slopes
Elevation 800-4000 m [2600-13100 ft] 1500-4000 m [4900-13100 ft] 500-2500 m [1600-8200 ft]
Distribution
from FNA
AK; ID; MT; WA; AB; BC; NT; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; OR; WA
[WildflowerSearch map]
[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.)

Micranthes idahoensis appears to hybridize with M. occidentalis where their ranges overlap. Intermediates are abundant in some populations along the Idaho-Montana border and in Montana. This phenomenon may explain the range of filament shapes found in M. occidentalis, from flattened to sightly club-shaped. The issue of the status of M. idahoensis with respect to M. marshallii (D. L. Krause and K. I. Beamish 1972) is best deferred until a thorough study of the whole complex over its entire range is done.

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

Source FNA vol. 8, p. 57. FNA vol. 8, p. 56. FNA vol. 8, p. 64.
Parent taxa Saxifragaceae > Micranthes 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. 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. 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
Synonyms Saxifraga lyallii, Saxifraga lyallii subsp. hultenii, Saxifraga lyallii var. hultenii Saxifraga odontoloma Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis
Name authority (Engler) Small: in N. L. Britton et al., N. Amer. Fl. 22: 143. 1905 , (Piper) A. Heller: Muhlenbergia 8: 60. 1912 , (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 ,
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