Southwestern waterwort Southwestern waterwort

Herbs, emergent on wet substrates, 1–6(–16) cm. Stems ascending or prostrate, branched. Leaves reddish green; stipules lanceolate, 0.5–0.6 mm, margins dentate, apex acute; petiole 0.5–1(–3) mm; blade oblong-lanceolate, 3–8 × (0.5–)1–2(–2.2) mm, base attenuate to rounded, apex obtuse to slightly emarginate. Pedicels 0–0.5 mm, erect. Flowers: sepals (2–)3, if 2, equal, if 3, 1 smaller, oblong-ovate or widely lanceolate, 1–1.5 × 1–1.5 mm; petals 3, pinkish white to reddish, elliptic or ovate, 1–1.5 × 0.5 mm; stamens 3; styles 3. Capsules oblong-ovoid, 3-locular, 1.5–2.5 mm diam. Seeds 10–20(–30) per locule, narrowly oblong, straight or curved to 15°, 0.5–0.7 × 0.1–0.3 mm; pits angular-hexagonal, length 1–2 times width, in 8–10 rows, 16–25(–30) per row.

Flowering summer. Muddy shores, shallow vernal pools, ditches, rice fields; 0–2900 m; Ariz., Calif., Colo., Idaho, Kans., Mont., Nebr., Nev., N.Mex., Oreg., S.Dak., Utah, Wyo.

Reports of Elatine rubella from southern British Columbia and Washington are based on misidentifications of E. brachysperma and E. chilensis, respectively.