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

alpine saxifrage, saxifrage des neiges, snow saxifrage

Habit Plants solitary or tufted, with bulbils on branched caudices, rhizomatous. Plants 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 flattened, (0.4–)1–4 cm;

blade ovate to ± round, sometimes elliptic or oblong, (0.5–)1–4 cm, thick, coriaceous, base attenuate to ± truncate, margins serrate to dentate on distal 2/3 (sometimes more), proximally ciliate, surfaces ± densely tangled, reddish brown-hairy abaxially, glabrous or glabrate adaxially.

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.

(5–)10–40-flowered, congested, almost capitate thyrses, (3–)7–20 cm, ± densely purple-tipped stipitate-glandular.

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).

sepals erect, spreading in fruit, ovate to deltate;

petals white, sometimes pink tinged, not spotted, oblong to ovate, clawed, 2–4 mm, ± equaling sepals;

filaments linear, flattened;

pistils connate ca. 1/2 their lengths;

ovary 1/2 inferior, appearing more superior in fruit.

Capsules

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

green, becoming reddish to purplish, folliclelike.

2n

= 60.

Micranthes nelsoniana

Micranthes nivalis

Phenology Flowering summer.
Habitat Open, mossy tundra, rocky ridges, or shady ledges
Elevation 0-1500 m (0-4900 ft)
Distribution
from FNA
AK; OR; WA; AB; BC; NT; NU; YT; Europe (ne Russia); Asia
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AB; BC; LB; NT; NU; QC; YT; Greenland; Europe; Asia (Himalayas, Kamchatka, Siberia)
[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 nivalis is closely related to M. tenuis. All records of M. nivalis in the United States (except Alaska) appear to be misapplied to or misidentifications of M. aprica, M. occidentalis, or M. rhomboidea. Occasional, dwarfed specimens of M. hieraciifolia and M. subapetala are similarly mislabelled.

(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. 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. 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. 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
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 Saxifraga nivalis
Name authority (D. Don) Small: in N. L. Britton et al., N. Amer. Fl. 22: 147. 1905 , (Linnaeus) Small: in N. L. Britton et al., N. Amer. Fl. 22: 136. 1905 ,
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