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Saxifraga oppositifolia

purple mountain saxifrage, purple or purple mountain saxifrage, purple saxifrage, saxifrage à feuilles opposées, twinflower saxifrage

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

Habit Plants mat- or cushion-forming (with trailing, ± woody stems), not stoloniferous, rhizomatous. Plants solitary or in clumps, not stoloniferous, with caudex or short-rhizomatous.
Leaves

cauline (marcescent, crowded), opposite (rarely alternate);

petiole absent;

blade oblong to ± broadly obovate, unlobed, 2–5 mm, leathery, margins entire, bristly-ciliate, with 1(–3) lime-secreting hydathodes (in pit, secretion obvious), apex obtuse, surfaces glabrous.

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.

Inflorescences

solitary flowers, ebracteate, 1–5 cm, glabrate or sparsely purple-tipped stipitate-glandular.

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.

Flowers

sepals erect, ovate, margins stiffly ciliate or not, surfaces hairy, stipitate-glandular, or glabrous;

petals purple to pink, rarely white, often drying violet, not spotted, obovate to elliptic, (2–)5–12(–20) mm, longer than sepals;

ovary ± superior.

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.

Capsules

± folliclelike.

2n

= 36, ca. 48, 50.

Saxifraga oppositifolia

Saxifraga mertensiana

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; CO; ID; MT; NY; OR; VT; WA; WY; AB; BC; MB; NS; NT; NU; ON; QC; YT; Eurasia; arctic and alpine
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CA; ID; MT; OR; WA; AB; BC
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies 7 (2 in the flora).

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

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

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

Key
1. Sepal margins bristly-ciliate
subsp. oppositifolia
1. Sepal margins glandular-ciliate
subsp. smalliana
Source FNA vol. 8, p. 136. FNA vol. 8, p. 146.
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. mertensiana, S. nathorstii, 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. nathorstii, S. oppositifolia, S. paniculata, S. radiata, S. rivularis, S. serpyllifolia, S. taylorii, S. tricuspidata, S. tridactylites, S. vespertina
Subordinate taxa
S. oppositifolia subsp. oppositifolia, S. oppositifolia subsp. smalliana
Synonyms S. mertensiana var. eastwoodiae
Name authority Linnaeus: Sp. Pl. 1: 402. 1753 , Bongard: Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 141. 1832 ,
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