Herbs, perennial, to 80 cm; rhizomes absent; stolons present; corms present. Leaves emersed or submersed, sessile, phyllodial, nearly terete; emersed, to 60 ´ 0.15--0.7 cm; submersed, 3.5--18.5 ´ 0.15--0.4 cm. Inflorescences racemes, of 1--4 whorls, emersed, 2.5--4 ´ 2.5--6 cm; peduncles 10--80 cm; bracts connate more than or equal to total length, subulate, 2--3 mm, delicate, not papillose; fruiting pedicels obliquely ascending, filiform, 1 cm. Flowers to 1.5 cm diam.; sepals recurved, not enclosing flower; filaments dilated, ± equaling anthers, pubescent; pistillate pedicellate, without ring of sterile stamens. Fruiting heads 0.6--1 cm diam.; achenes obovoid-cuneate, abaxially keeled, 2--3 ´ 1.2--1.5 mm, beaked; faces not tuberculate, wings absent, glands 1--2; beak erect to horizontal, 0.3--0.4 mm. 2n = 22.

Flowering summer (Jul--Sep). Sandy pond shores and swamps of acid waters, mainly along Atlantic Coastal Plain; 0--100 m; Mass., N.J., N.Y., R.I.

Erect aquatic with long, slender rhizomes; lvs phyllodial, nodose, terete, attenuate, 3-20 cm, occasionally with a small blade; scape 1-8 dm; fls in 2-4 whorls, the upper staminate, the lower pistillate, both on slender, ascending-spreading pedicels 1-3 cm, usually only 1 or 2 fruiting; bracts small, ovate, 2-3 mm, connate nearly or fully throughout; sep ovate, obtuse, 3-5 mm, reflexed in fr; pet 3-6 mm; stamens 12-15; filaments dilated, roughened with minute scales; achenes 2-3 mm, with 1-3 prominent wings on each face, these and the dorsal wing crenulate; beak erect to horizontal, 0.3-0.4 mm; 2n=22. On sandy soil in shallow, acid water from Mass. to N.Y., often with no. 4 [Sagittaria engelmanniana J. G. Sm.. Aug., Sept.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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