Abhandlungen herausgegeben vom naturwissenschaftlichen Vereine zu Bremen 2: 490. 1871.
Herbs, perennial, to 40 cm, on tidal muds; rhizomes absent; stolons present; corms present. Leaves submersed, phyllodial, lenticular, 5–40 ´ 0.1–0.4 cm, or rarely floating; petiole terete, 2.4–4 cm; blade linear-lanceolate to ovate, 1–2.5 ´ 0.3–1.5 cm. Inflorescences racemes, of 2–7 whorls, floating, 2–11 ´ 1.5–4.5 cm; peduncles 5–40 cm; bracts connate more than ¼ total length, subulate, 1.5–4.2 mm, delicate, not papillose; fruiting pedicels recurved, cylindric to club-shaped, 0.2–1.1 cm. Flowers 0.4–1.2 cm diam.; sepals spreading to recurved in staminate, erect in pistillate, enclosing flower or fruiting head; filaments dilated, longer than anther, glabrous; pistillate pedicellate, occasionally with ring of sterile stamens. Fruiting heads 0.55–0.8 cm diam.; achenes oblanceoloid, abaxially keeled, 2 ´ 1.5 mm, beaked; faces not tuberculate, wings 1–2, crenate, glands 0–1; beak lateral, erect, 0.2–0.4 mm. 2n = 22.
Phenology: Flowering summer–fall.
Habitat: Streams and brackish bays
Elevation: 0–100 m
Ala., Conn., Del., D.C., Fla., Ga., Md., Mass., Miss., N.J., N.Y., N.C., Pa., R.I., S.C., Va., South America (Colombia)
Sagittaria subulata occurs in shallow brackish waters near the coast. The plants are especially common in areas that are exposed during low tides.