Herbs, perennial, floating aquatic, without caudex or rhizomes, monoecious, 0.5–13 dm; branching not phyllanthoid. Stems terete, not winged, glabrous. Leaves distichous; all well developed; stipules auriculate, pale brown; blade ± orbiculate, 9–17 mm diam., base cordate, apex rounded to shallowly emarginate, both surfaces papillate. Inflorescences cymules, bisexual, with 1–2 staminate and 1–2 pistillate flowers, or flowers solitary. Pedicels: staminate 0.5–1 mm, pistillate spreading in fruit, 0.5–1 mm. Staminate flowers: sepals (5–)6, white or greenish white, flat, 1–1.4 mm; nectary extrastaminal, (5–)6 glands; stamens 3, filaments distinct. Pistillate flowers: sepals (5–)6, white or greenish white, flat, 0.8–1.2 mm, 1-veined; nectary annular, unlobed to lobed. Capsules 2.5–3 mm diam., smooth. Seeds uniformly brown, 1–1.4 mm, verrucose.
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