Herbs, perennial, to 112 cm; rhizomes not coarse; stolons absent; corms absent. Leaves submersed and emergent; petiole triangular, 11.5--35 cm; blade elliptic to ovate, 25--56 cm. Inflorescences racemes or panicles, of 4--10 whorls, emersed, 8--25 ´ 5--36 cm; peduncles to 76 cm; bracts connate ¼ total length, lanceolate, 4--8 mm, papillose; fruiting pedicels ascending to spreading, cylindric, 1--4.5 cm. Flowers to 3 cm diam.; sepals appressed to spreading; filaments slightly dilated, shorter than anthers, glabrous; pistillate pedicellate, without ring of sterile stamens. Fruiting heads 0.7--1 cm diam.; achenes obovoid, abaxially keeled, 1.2--1.5 ´ 0.7--1.1 mm, beaked; faces not tuberculate, wings 1, ± entire, glands 0--1; beak lateral, erect, 0.1--0.3 mm.

Flowering spring--fall. Swamps, marshes, bogs, ditches, borders of lakes; 0--300 m; Ark., La., Okla., Tex.