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Idaho saxifrage

alpine saxifrage, Tolmie's alpine saxifrage, Tolmie's saxifrage

Habit Plants solitary or tufted, with bulbils on caudices. Plants mat-forming, (stems trailing, thin, basally slightly woody), with slender, woody caudices.
Leaves

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.

cauline, proximally crowded;

petiole absent;

blade elliptic-obovate, 0.8–1.5 cm, fleshy, base cuneate, margins entire, sometimes proximally sparsely long-ciliate, surfaces glabrous.

Inflorescences

15+-flowered, open thyrses, (flowers ± crowded at tips, becoming more open in fruit), 10–40 cm, purple-tipped stipitate-glandular.

2–10-flowered, lax cymes, sometimes solitary flowers, 3–12 cm, glabrous or purplish- or pink-tipped stipitate-glandular; (bracts 1–3, proximal).

Flowers

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).

sepals erect to spreading, ovate;

petals white, not spotted, linear to oblanceolate, 2.5–5 mm, longer than sepals, short- or not clawed;

filaments broadly club-shaped (± petaloid);

pistils connate to 1/2 their lengths;

ovary ± superior (to 1/4 adnate to hypanthium).

Capsules

green to reddish purple, folliclelike.

green, purple mottled, valvate.

2n

= 20.

= 30.

Micranthes idahoensis

Micranthes tolmiei

Phenology Flowering spring–early summer. Flowering summer.
Habitat Open ledges and slopes Arctic and alpine tundra, fell-fields
Elevation 500-2500 m (1600-8200 ft) 500-4000 m (1600-13100 ft)
Distribution
from FNA
ID; MT; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; ID; MT; NV; OR; UT; WA; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Unlike those of most Micranthes species, the leaves of M. tolmiei are proximally cauline and the ovules have two integuments. The seeds have a loose, winglike testa.

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

Source FNA vol. 8, p. 64. FNA vol. 8, p. 54.
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. 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. 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. unalaschcensis, M. virginiensis
Synonyms Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis Saxifraga tolmiei, Saxifraga tolmiei var. ledifolia
Name authority (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 , (Torrey & A. Gray) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1022. 2007 ,
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