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Idaho saxifrage

Columbian saxifrage, grassland saxifrage, northwestern saxifrage, smooth leaf saxifrage, swamp saxifrage, whole-leaf saxifrage

Habit Plants solitary or tufted, with bulbils on caudices. Plants solitary or in clumps, (sometimes gynodioecious), often with bulbils on caudices, or short-rhizomatous.
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.

basal;

petiole flattened, 0.5–4 cm;

blade narrowly to broadly ovate, 2–7 cm, ± leathery, base attenuate, margins entire or minutely denticulate, usually ciliate, surfaces sparsely to moderately hairy.

Inflorescences

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

(15–)20+-flowered, open to ± congested, conic thyrses, (usually branched, lateral cymules ± open), 12–35 cm, densely pink- to purple-tipped stipitate-glandular.

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 spreading to slightly reflexed, ovate;

petals white, not spotted, obovate, clawed, 2–4 mm, longer than sepals;

filaments linear, flattened;

pistils connate to 1/2 their lengths;

ovary 1/2+ inferior.

Capsules

green to reddish purple, folliclelike.

reddish or purplish, folliclelike.

2n

= 20.

= 38.

Micranthes idahoensis

Micranthes integrifolia

Phenology Flowering spring–early summer. Flowering late winter–spring.
Habitat Open ledges and slopes Vernally moist meadows, grassy slopes, rock outcrops
Elevation 500-2500 m (1600-8200 ft) 0-1800 m (0-5900 ft)
Distribution
from FNA
ID; MT; OR; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR; 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.)

The occasional occurrence of sterile pollen has been noted in this as well as in other species of Micranthes (as Saxifraga, K. I. Beamish 1961). Some populations exhibit gynodioecism (P. E. Elvander 1982).

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

Source FNA vol. 8, p. 64. FNA vol. 8, p. 67.
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. 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 idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis Saxifraga integrifolia
Name authority (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 , (Hooker) Small: in N. L. Britton et al., N. Amer. Fl. 22: 137. 1905 ,
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