N. Amer. Sagittaria. 16, plate 11. 1894.
Herbs, perennial, to 100 cm; rhizomes absent; stolons present; corms present. Leaves emersed; petiole 5-ridged, ascending to erect, 24.5–60 cm; blade sagittate, 11.5–26.5 × 0.8–15 cm, basal lobes longer than remainder of blade. Inflorescences racemes, rarely panicles, of 5–17 whorls, emersed, 20–37 × 5–27 cm; peduncles 25–96 cm; bracts connate more than or equal to ¼ total length, lanceolate, 6.5–15 mm, delicate, not papillose; fruiting pedicels spreading, cylindric, 1.5–4.4 cm. Flowers to 3 cm diam.; sepals recurved to spreading, not enclosing flower; filaments cylindric, shorter than anthers, glabrous; pistillate flowers pedicellate, without ring of sterile stamens. Fruiting heads 0.9–1.5 cm diam; achenes oblanceoloid, abaxially keeled, 1.2–2.5 × 0.8–1.6 mm, beaked; faces tuberculate, wings absent, glands 0–1; beak lateral, erect, 0.1–0.6 mm.
Phenology: Flowering summer–fall.
Habitat: Wet ditches, ephermeral pools, and margins of streams and lakes
Elevation: 0–300 m
Ariz., Calif., Kans., Nebr., Okla., Tex., Mexico, Central America (Nicaragua)