Flora of North America species comparison

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Micranthes nelsoniana

Micranthes nelsoniana var. porsildiana

dotted saxifrage, heartleaf saxifrage, Nelson's saxifrage, saxifrage
Photo is of parent taxon

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

blades thin, not fleshy, margins 12–18-toothed.
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.

congested, tangled-ascending hairy.
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).

Pistils

connate to 3/4 their lengths.
Capsules

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

3–8 mm.
2n

= 28.

Micranthes nelsoniana

Micranthes nelsoniana var. porsildiana
Phenology Flowering summer.
Habitat Stream banks, wet areas
Elevation 0-2500 m (0-8200 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; NT; NU; YT
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.)

The characters used by J. A. Calder and D. B. O. Savile (1960) to separate var. porsildiana from var. pacifica overlap more significantly than do the characters that separate their subspecies, although inland populations of what has been called var. porsildiana gradually tend away from the morphology typical of coastal populations. Elven and Murray treated this taxon as a species distinct from Micranthes nelsoniana, because it apparently grows in stands mixed with other subspecies of M. nelsoniana without forming intermediates. The entire complex needs a thorough re-examination.

(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. 56.
Parent taxa Saxifragaceae > Micranthes Saxifragaceae > Micranthes > Micranthes nelsoniana
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. nelsoniana var. carlottae, M. nelsoniana var. cascadensis, M. nelsoniana var. insularis, M. nelsoniana var. nelsoniana
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 punctata subsp. porsildiana, M. porsildiana, Saxifraga nelsoniana subsp. pacifica, Saxifraga nelsoniana var. pacifica, Saxifraga nelsoniana subsp. porsildiana, Saxifraga nelsoniana var. porsildiana, Saxifraga punctata subsp. pacifica, Saxifraga punctata var. pacifica, Saxifraga punctata var. porsildiana
Name authority (D. Don) Small: in N. L. Britton et al., N. Amer. Fl. 22: 147. 1905 , (Calder & Savile) Gornall & H. Ohba: J. Bot. Res. Inst. Texas 2: 395. (2008)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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