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dotted saxifrage, heartleaf saxifrage, Nelson's saxifrage, saxifrage

Michaux's saxifrage

Habit Plants solitary or tufted, with bulbils on branched caudices, rhizomatous. Plants solitary or tufted, with bulbils on caudices.
Leaves

basal;

petiole rounded, 3–30 cm;

blade reniform to round, 2–9 cm, thin or slightly fleshy, sometimes thick and fleshy, base cordate, margins deeply crenate, eciliate or sparsely short glandular-ciliate, surfaces glabrous or ± hairy.

basal;

petiole somewhat flattened, 2–6 cm;

blade oblanceolate, 2–12 cm, thin, basecuneate to ± attenuate, margins usually 15+-toothed (teeth large, lobelike), densely long glandular-ciliate, surfaces hairy.

Inflorescences

10+-flowered, ± open, lax to congested, conic, sometimes also glomerate thyrses, 10–35 cm, tangled-hairy (pilose-arachnoid) at least distally, sometimes also purple- or brown-tipped stipitate-glandular.

30+-flowered, very open, lax thyrses, (flowers rarely replaced by bulbils), 10–40 cm, densely tangled, purple-tipped stipitate-glandular; (bracts leaflike, gradually reduced distally).

Flowers

sepals reflexed, ± ovate;

petals white to pinkish, rarely orange-spotted, ovate to oblong, narrowly to broadly clawed, 2.5–4.5 mm, longer than sepals;

filaments distinctly club-shaped;

pistils connate 1/2–3/4 their lengths;

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

slightly bilaterally symmetric;

sepals reflexed, oblong to elliptic;

petals white, 3 with 2 basal yellow spots, 2 without spots, oblanceolate to spatulate, clawed, 3–4.5 mm, longer than sepals;

filaments linear, flattened;

pistils connate 1/2+ their lengths;

ovary superior.

Capsules

green to yellow and purplish tinged to dark purple, valvate.

green to yellow, sometimes purple tinged, valvate

Micranthes nelsoniana

Micranthes petiolaris

Phenology Flowering late spring–early autumn.
Habitat Wet ledges, boulderfields, and rocky slopes, usually in thin soil over rock
Elevation 500-2100 m (1600-6900 ft)
Distribution
from FNA
AK; OR; WA; AB; BC; NT; NU; YT; Europe (ne Russia); Asia
[WildflowerSearch map]
[BONAP county map]
from FNA
GA; KY; MD; NC; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 6 (5 in the flora).

Although sometimes reported for North America, Saxifraga nelsoniana var. aestivalis (Fischer & C. A. Meyer) H. Ohba (S. aestivalis Fischer & C. A. Meyer) is found only in Eurasia.

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

Micranthes petiolaris (Rafinesque) Brouillet & Gornall is an isonym.

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

Key
1. Inflorescences purple- or brown-tipped stipitate- glandular.
var. nelsoniana
1. Inflorescences tangled-hairy
→ 2
2. Leaf blade margins 9-12-toothed; capsules 6-12 mm; mostly Queen Charlotte Islands, adjacent coastal British Columbia.
var. carlottae
2. Leaf blade margins 12-18-toothed; capsules 3-8 mm; Oregon to Alaska and nw Canada
→ 3
3. Inflorescences somewhat lax, hairs appressed; Coast Ranges and Cascades, British Columbia, Oregon, Washington.
var. cascadensis
3. Inflorescences congested, hairs ascending; nw Canada, Alaska
→ 4
4. Leaf blades thick, fleshy; pistils connate most of their lengths; Aleutian Islands, Alaska.
var. insularis
4. Leaf blades thin, not fleshy; pistils connate to 3/4 their lengths; nw Canada, Alaska.
var. porsildiana
Source FNA vol. 8, p. 54. FNA vol. 8, p. 58.
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. idahoensis, M. integrifolia, M. lyallii, M. marshallii, M. micranthidifolia, 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. 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
Subordinate taxa
M. nelsoniana var. carlottae, M. nelsoniana var. cascadensis, M. nelsoniana var. insularis, M. nelsoniana var. nelsoniana, M. nelsoniana var. porsildiana
Synonyms Saxifraga nelsoniana, Saxifraga punctata subsp. nelsoniana, Saxifraga punctata var. nelsoniana Hexaphoma petiolaris, Saxifraga michauxii, Saxifraga petiolaris
Name authority (D. Don) Small: in N. L. Britton et al., N. Amer. Fl. 22: 147. 1905 , (Rafinesque) Bush: Amer. Midl. Naturalist 11: 225. 1928 ,
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