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Merten's or wood or woodland saxifrage, Mertens' saxifrage, wood saxifrage, woodland saxifrage

alpine-brook saxifrage, weak saxifrage

Habit Plants solitary or in clumps, not stoloniferous, with caudex or short-rhizomatous. Plants (delicate), loosely tufted or matted, (green to purple), stoloniferous, weakly rhizomatous, (with bulbils in axils of basal leaves).
Leaves

basal and cauline, (basal persistent, cauline ± inconspicuous);

petiole rounded, 2–20 mm;

blade round to reniform, irregularly shallowly lobed, 20–80(–100) mm, thin, margins serrate, stipitate glandular-ciliate, apex obtuse to rounded, surfaces sparsely hairy.

basal and cauline;

petiole ± flattened, 2–30(–50) mm;

blade reniform, 3–5(–7)-lobed (lobes rounded, sometimes ± obtuse, distalmost unlobed), (2.6–)3.7–5.2(–7.4) mm, slightly fleshy, margins entire, eciliate or sparsely glandular-ciliate, without lime-secreting hydathodes (with nonsecreting hydathodes at lobe apices), apex acute, surfaces glabrous.

Inflorescences

30+-flowered, open, much-branched thyrses, usually some or all flowers replaced by bulbils (sometimes bulbils absent), 15–40 cm, dark purple-tipped stipitate-glandular;

bracts (± inconspicuous), petiolate or sessile.

2–3(–5)-flowered cymes, sometimes solitary flowers, (flowers pedicellate), 1.7–7 cm, glabrous or sparsely to ± densely tangled, pink-tipped stipitate-glandular;

bracts (2–3), petiolate, (unlobed or 1–3-lobed, reduced).

Flowers

sepals reflexed (at least in fruit), ovate to elliptic, margins eciliate, surfaces sparsely stipitate-glandular or glabrous;

petals white, not spotted, narrowly ovate to elliptic, (3–)4–6 mm, longer than sepals;

filaments strongly club-shaped;

ovary superior.

(hypanthium U-shaped in longisection);

sepals erect, (sometimes rusty brown), elliptic to ovate, margins eciliate or sparsely glandular-ciliate, glabrous or sparsely to densely stipitate-glandular;

petals white, sometimes pink tinged, not spotted, oblong to elliptic, 2–6 mm, to 2–3 times length of sepals;

ovary 1/2 inferior.

2n

= 36, ca. 48, 50.

Saxifraga mertensiana

Saxifraga rivularis

Phenology Flowering spring–summer.
Habitat Moist to wet stream banks, mossy cliffs and slopes, waterfall spray zones
Elevation 0-2500 m (0-8200 ft)
Distribution
from FNA
AK; CA; ID; MT; OR; WA; AB; BC
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; NH; NU; QC; n Eurasia
[WildflowerSearch map]
[BONAP county map]
Discussion

Plants of Saxifraga mertensiana bear bulbils in the axils of basal leaves.

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

Subspecies 2 (2 in the flora).

Some reports of Saxifraga sibirica Linnaeus from Canada are misidentifications of this species.

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

Key
1. Plants wholly green or purple only in inflorescences; hair crosswalls usually without color, rarely pale purple; inflorescences 2.7-7 cm, glabrous or sparsely stipitate-glandular; hypanthia sparsely short stipitate-glandular, hairs 0.1-0.3(-0.4) mm.
subsp. rivularis
1. Plants mostly purple (at least inflorescences); hair crosswalls purple; inflorescences 1.7-3 cm, sparsely to densely stipitate-glandular; hypanthia sparsely to densely long stipitate-glandular, hairs (0.2-)0.3-0.6(-1.1) mm.
subsp. arctolitoralis
Source FNA vol. 8, p. 146. FNA vol. 8, p. 144.
Parent taxa Saxifragaceae > Saxifraga Saxifragaceae > Saxifraga
Sibling taxa
S. adscendens, S. aizoides, S. aleutica, S. bracteata, S. bronchialis, S. cernua, S. cespitosa, S. cherlerioides, S. chrysantha, S. debilis, S. eschscholtzii, S. flagellaris, S. hirculus, S. hyperborea, S. nathorstii, S. oppositifolia, S. paniculata, S. radiata, S. rivularis, S. serpyllifolia, S. taylorii, S. tricuspidata, S. tridactylites, S. vespertina
S. adscendens, S. aizoides, S. aleutica, S. bracteata, S. bronchialis, S. cernua, S. cespitosa, S. cherlerioides, S. chrysantha, S. debilis, S. eschscholtzii, S. flagellaris, S. hirculus, S. hyperborea, S. mertensiana, S. nathorstii, S. oppositifolia, S. paniculata, S. radiata, S. serpyllifolia, S. taylorii, S. tricuspidata, S. tridactylites, S. vespertina
Subordinate taxa
S. rivularis subsp. arctolitoralis, S. rivularis subsp. rivularis
Synonyms S. mertensiana var. eastwoodiae
Name authority Bongard: Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 141. 1832 , Linnaeus: Sp. Pl. 1: 404. (1753)
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