1. Elatine californica A. Gray, Proc. Amer. Acad. Arts. 13: 361, 364. 1878.
California waterwort California waterwort
Elatine californica var. williamsii (Rydberg) Fassett; E. williamsii Rydberg
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.
Flowering summer. Pools, pond shores, rice fields, stream banks; 0–1900(–2600) m; Ariz., Calif., Idaho, Mont., Nev., N.Mex., Oreg., Utah, Wash.; Mexico (Baja California).
Elatine californica is distinguished from other species of the genus by having long pedicels that are recurved in fruit and strongly curved seeds that can be nearly circular.