Glabrous herb. Leaves submerged or emerged, linear or linear-lanceolate to oblong-elliptic, attenuate at the base, obtuse; petiole short or absent. Panicle similar to that of Alisma lanceolatum, with somewhat recurved branches and pedicels. Flowers white to purplish-white, c. 8 mm across; pedicel thickened, up to 5 cm long; bracts lanceolate-ovate. Sepals ovate, 1.5-2.5 mm long, acute. Petals obovate, 2.5-3.5 mm long, 2-3.5 mm broad, obtuse. Stamens shorter than the ovaries; anthers somewhat orbicular or isodiametric. Ovaries subovate, c. 1 mm long; styles recurved, shorter than ovaries, papillate in the upper 1/4-1/2 part. Achenes somewhat obovate, c. 2.5 mm long, 3 ridged on the back.