Herbs, submersed or growing on exposed but wet substrates, 1–5 cm. Stems decumbent to erect, branched. Leaves light green to green, sometimes becoming reddish in terrestrial plants; stipules lanceolate, 0.5–0.6 mm, margins dentate, apex acute; petiole 1–4 mm; blade obovate to oblanceolate, 4–12(–15) × 1.2–3 mm, base narrowly cuneate, apex acute to obtuse. Pedicels 1.5–2.5(–3.5) mm, recurved in fruit. Flowers: sepals 4, usually equal, sometimes 1 reduced, oblong-ovate or widely lanceolate, 0.5–0.6 × 0.3–0.4 mm; petals 4, greenish white, slightly reddish, or pink, elliptic or ovate, 1–1.5 × 0.5–0.6 mm; stamens 8; styles 4. Capsules depressed-ovoid, 4-locular, 1.3–2.5 mm diam. Seeds 2–5 per locule, oblong to ellipsoid, curved 90–180°, 0.6–1 × 0.2 mm; pits elliptic, length 1–3 times width, in 6–10 rows, (16–)20–29 per row.