Herbs perennial, subaquatic. Roots fibrous, subequally thick. Stems elongated, glabrous or appressed puberulent above, short branched, often rooting at nodes. Stem leaves with petiole 0.5--2 cm, glabrous or sparsely puberulent; blade 3-partite near base, orbicular-reniform or cordate-pentagonal, 0.4--1 × 0.6--1.7 cm, herbaceous, subglabrous or abaxially sparsely appressed puberulent, base cordate, central lobe cuneate-rhombic, 3-lobed; lateral lobes obliquely obovate or obliquely flabellate, unequally 2-partite, ultimate lobules narrowly ovate or linear-lanceolate. Monochasium terminal, 1--4-flowered; bracts subsessile, leaflike or undivided, narrowly ovate, 0.5--7 mm. Flowers 0.4--0.9 cm in diam. Pedicel to 3.5 cm, glabrous or sparsely puberulent. Receptacle sparsely puberulent. Sepals 5, ovate-elliptic, 2.2--3 mm, glabrous. Petals 5, narrowly obovate or obovate, 2.2--4 × 1.5--2.5 mm, nectary pit without a scale, apex rounded. Stamens 12 or numerous; anthers ellipsoid. Aggregate fruit subglobose, 3--4 mm in diam.; carpels numerous. Achene broadly ellipsoid or obliquely obovoid, 1--1.3 × 0.8--1 mm, glabrous, margin with corky thickening; style persistent, ca. 0.3 mm. Fl. Jun--Aug, fr. Sep.

Streams, moist places by streams, meadows. Heilongjiang, Jilin, NE Nei Mongol [Japan, Mongolia, Russia (Siberia); N Europe].