21. Saxifraga rivularis Linnaeus, Sp. Pl. 1: 404. 1753.
Plants (delicate), loosely tufted or matted, (green to purple), stoloniferous, weakly rhizomatous, (with bulbils in axils of basal leaves). Leaves 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 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 (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.
Subspecies 2 (2 in the flora): n North America, n Eurasia.
Some reports of Saxifraga sibirica Linnaeus from Canada are misidentifications of this species.