Plants aquatic, 4-15 cm. Rhizomes sympodial, proliferatively spreading, filiform, units 2-30 cm × 1-2 mm, roots restricted to nodes. Stems erect, 1-2.5 dm × 2-3 mm. Leaves 2-4 on fertile shoots, sessile; blade elliptic, 5-12 × 2.5-4 cm; base narrowly tapering; apex acute or acuminate. Inflorescences racemose, simple, 5-15-flowered. Flowers 3-merous; tepals conspicuous, 2.5-4 × 1.5-2 mm; filaments 1.5-2 mm; anthers 0.5-0.7 mm; ovary globose or cylindrical, 2-2.5 × 1.5-2.4 mm; style 0.5-1.5 mm; stigma distinctively 3-lobed; pedicel 1-3 × 0.5 mm. Berries green with fine red spots when young, maturing to red, globose, 4-6 mm diam. Seeds 1-3, globose, 2 mm. 2n = 36. Flowering May--Jun, fruits retained through Sep. Often forming dense clonal patches in sphagnum bogs, muskegs, and wet forests; 0--1000 m; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Conn., Maine, Mass., Mich., Minn., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., Wis.; Asia (Siberia).