Nathaniel Lord Britton & Addison Brown

“ Stem stout, 2°-31⁄2° high; leaves 1°-2° long, strongly keeled, 11⁄2"-6" wide; bracts similar to the leaves but shorter; inflorescence simple or somewhat branched, with the branches, or heads, axillary, the main axis bearing 2-4 sessile pistillate heads and 6-10 staminate heads, the branches, when present, bearing 1 pistillate head and sometimes 1-4 staminate heads; fruiting heads about 15" in diameter; nutlets olive-brown, shining, the body fusiform, about 4" long; stigma linear, 11⁄4"-13⁄4" long. ”

“ Leaves linear, flat, slightly keeled beneath, the lowest 3°-5° long; staminate heads, numerous; pistillate heads 2-4 on the stem or branches, sessile or more commonly peduncled, hard, compact and 10"-16" in diameter; style 1; stigmas 1-2; nutlets sessile, 3"-5" long, obtusely 4-5-angled, narrowed at the base, the top rounded, flattened or depressed, abruptly tipped with the style; scales as long or nearly as long as the fruit, often with 2 or 3 other exterior ones, somewhat spatulate, the apex rounded, denticulate or eroded. ”

“ Marsh or pond plants with creeping rootstocks and fibrous roots, erect or floating simple or branched stems, and linear alternate leaves, sheathing at the base. Flowers monoecious, densely crowded in globose heads at the upper part of the stem and branches, the staminate heads uppermost, sessile or peduncled. ”