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Howell's saxifrage

Idaho saxifrage

Habit Plants solitary or in groups, with bulbils on caudices. Plants solitary or tufted, with bulbils on caudices.
Leaves

basal;

petiole flattened, 1–4 cm;

blade oblong to narrowly ovate, 1–2(–3) cm, ± fleshy, base attenuate, margins sharply serrate, eciliate, surfaces sparsely tangled, reddish brown-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

5–10(–20)-flowered, very open, lax, ± flat-topped cymes or thyrses, 5–10(–20) cm, glabrate to sparsely purple-tipped stipitate-glandular; (bracts glabrous).

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

Flowers

sepals strongly reflexed, elliptic, (surfaces glabrous);

petals white, not spotted, obovate to elliptic, clawed, 2.5–4.5 mm, longer than sepals;

filaments linear, flattened;

pistils distinct almost to base;

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

purple, valvate.

green to reddish purple, folliclelike.

2n

= 20.

Micranthes howellii

Micranthes idahoensis

Phenology Flowering early spring–early summer. Flowering spring–early summer.
Habitat Wet, rocky ledges and crevices Open ledges and slopes
Elevation 0-900 m (0-3000 ft) 500-2500 m (1600-8200 ft)
Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
ID; MT; OR; WA
[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.)

Source FNA vol. 8, p. 63. FNA vol. 8, p. 64.
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. 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. 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 howellii Saxifraga idahoensis, Saxifraga marshallii subsp. idahoensis, Saxifraga marshallii var. idahoensis, Saxifraga occidentalis var. idahoensis
Name authority (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 140. (1905) (Piper) Brouillet & Gornall: J. Bot. Res. Inst. Texas 1: 1020. 2007 ,
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