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Howell's saxifrage

diamond-leaf 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, 1–3 cm;

blade broadly ovate to triangular, 1–3 cm, fleshy, base attenuate, margins coarsely serrate, ciliate, surfaces sparsely to moderately tangled, reddish brown-hairy abaxially, glabrous 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).

(5–)10–40-flowered, congested, ± glomerate or capitate thyrses, 4–20 cm, usually densely yellow- to cream-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 ascending, ovate;

petals white, not spotted, oblong to elliptic, clawed, 2–4 mm, 1.5+ times as long as sepals;

filaments linear, flattened;

pistils connate to 1/2 their lengths;

ovary inferior, appearing more superior in fruit.

Capsules

purple, valvate.

purple, folliclelike.

2n

= 20, 38, 40, 56.

Micranthes howellii

Micranthes rhomboidea

Phenology Flowering early spring–early summer. Flowering late spring–summer.
Habitat Wet, rocky ledges and crevices Subalpine and alpine meadows
Elevation 0-900 m (0-3000 ft) 1500-4600 m (4900-15100 ft)
Distribution
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; ID; MT; NM; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Micranthes rhomboidea is somewhat polymorphic; variants have been given taxonomic designations with little consistency. The chromosome number variation needs thorough study, as in other species of Micranthes, because no obvious correlations with morphology or geographic distribution are known (B. L. Bethers 1973). Reports from Canada (Alberta, Saskatchewan) were rejected as misidentifications of M. occidentalis.

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

Source FNA vol. 8, p. 63. 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. 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. 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. 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 rhomboidea, Saxifraga austrina, Saxifraga rhomboidea var. austrina, Saxifraga rhomboidea var. franciscana
Name authority (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 140. (1905) (Greene) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. 1905 ,
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