Herbs perennial, subaquatic. Roots fibrous, subequally thick. Stems 10--40 cm, glabrous, branched, often rooting at nodes. Basal leaves 3--5; petiole 2.5--11 cm, glabrous; blade 3-lobed, cordate-pentagonal or orbicular-reniform, 0.7--2.1 × 1.1--3.7 cm, herbaceous, glabrous, base cordate, central lobe broadly cuneate or broadly obovate, undivided or 3-lobed, apex rounded; lateral lobes larger, obliquely broadly obovate, undivided or unequally 2-lobed. Stem leaves similar to basal ones, gradually reduced upward; petiole sometimes sparsely puberulent. Flowers leaf-opposed, terminal, or 2 in a monochasium, 0.6--0.9 cm in diam. Pedicel 1--4 cm, glabrous or sparsely puberulent. Receptacle sparsely puberulent. Sepals 5, orbicular-ovate, 2.3--3 mm, glabrous. Petals 5, obovate, 2.5--4.2 × 2--3.2 mm, nectary pit without a scale, apex rounded. Stamens numerous; anthers oblong. Aggregate fruit broadly ellipsoid or broadly ovoid, 5--6 mm in diam.; carpels numerous. Achene slightly bilaterally compressed, obliquely obovoid, 1.3--1.6 × 1--1.2 mm, glabrous, margin with corky thickening; style persistent, ca. 0.1 mm. Fl. Jun--Aug, fr. Jul--Aug.
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