16. Saxifraga cernua Linnaeus, Sp. Pl. 1: 403. 1753.
Nodding saxifrage, saxifrage penchée Nodding saxifrage, saxifrage penchée
Plants solitary or in tufts, not stoloniferous, weakly rhizom-atous, with small caudex. Leaves basal and cauline, (basal usually ephemeral, gradually dying through growing season, cauline conspicuous, reduced distally); petiole flattened, (5-)10-60(-90) mm; blade round to reniform, 3-7(-9)-lobed usually less than halfway to midvein (distal unlobed), (3-)5-18(-20) mm, slightly fleshy, margins entire, eciliate or sometimes sparsely glandular-ciliate, apex rounded, sometimes acute, surfaces glabrous or sparsely stipitate-glandular. Inflorescences 2(-5)-flowered paniculate or racemelike thyrses, sometimes solitary flowers, (flowers nodding in bud), some or all flowers but terminal one on each branch often replaced by bulbils, 3-30 cm, stipitate-glandular; bracts (proximal ephemeral), petiolate or sessile. Flowers: sepals erect, (sometimes reddish), oblong, margins glandular-ciliate, surfaces short-stipitate-glandular; petals white, not spotted, obovate to spatulate, 5-12 mm, longer than sepals; ovary superior. 2n = 24, 36, 48, 52, 56, 60, 70, 72.
Flowering summer. Cool, wet areas, mossy banks, tundra, shady rock faces, late snowbeds; 0-4300 m; Greenland; Alta., B.C., Man., Nfld. and Labr. (Labr.), N.W.T., Nunavut, Ont., Que., Yukon; Alaska, Colo., Idaho, Minn., Mont., Nev., N.H., N.Mex., S.Dak., Utah, Wash., Wyo.; Eurasia.
Saxifraga cernua plants rarely set seed; they bear bulbils among the basal leaves. Some reports of S. sibirica Linnaeus from Canada are misidentifications of this species.