Stem usually floating and elongate; lvs floating, rounded on the back, 2–6 mm wide; upper lvs and bracts conspicuously dilated at base; infl unbranched; pistillate heads 1–3, the lowest supra-axillary and usually peduncled, the others axillary, usually sessile, 1–2 cm thick when ripe; tep spatulate, erose, two-thirds as long as the frs; achenes brown, dull, the body 3–5 mm, fusiform, abruptly contracted to a 1 mm beak; staminate part of the infl 1–4 cm, the 1–6 heads close together; 2n=30. In deep or shallow water, occasionally on mud; Nf. to Alas., s. to N.J., Pa., Mich., and Calif.
Home