This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Sparganium simplex multipedunculata Morong, Bull. Torrey Club 15: 79. 1888.
Sparganium multipedunculatum Rydb. Bull. Torrey Club 32: 598. 1905.
Stem i°-i 2/3° high or less, or floating, rather slender; leaves narrow, 2 1/2"-5" wide or rarely less, slightly keeled, dilated and scarious-margined at the base; bracts similar to the leaves, but relatively more dilated at the base; inflorescence usually simple, the pistillate heads 2-5, the lower 1 or 2 decidedly pedun-cled, some of them supra-axillary, the staminate heads 3-5, approximate to each other, but usually distant from the nearest pistillate one; fruiting heads 7"-10" in diameter; nutlets brown, the body fusiform, about 2" long; stigma linear, about 1/2" long.
Sparganium angustifolium Michx. Fl. Bor. Am. 2: 189.
1803. Sparganium nutans angustifolium Pursh, Fl. Am. Sept. 34.
1814. Sparganium simplex angustifolium Torr. Fl. N. Y. 2: 249.
Stem floating and elongated, or occasionally 1/2°-1° high; leaves usually very narrow, 1 1/2"-2" wide, not keeled; bracts various, the lower ones similar to the leaves, dilated and sometimes slightly scarious-margined at the base, the upper ones much shorter than the lower, lanceolate to ovate; inflorescence simple, the pistillate heads 2-4, the lower 1 or 2 usually on supra-axillary peduncles, the staminate heads usually approximate; fruiting heads 7"-8" in diameter; nutlets dirty-brown, except the reddish brown bases, the body constricted at the middle or above it; stigma 1/2" long or less.
In slow streams and ponds, Newfoundland to British Columbia, Connecticut, Pennsylvania, Colorado and California. Illustrated in first edition as Sparganium simplex. July-Sept.
Sparganium simplex fluitans Engelm.; A. Gray Man.
Ed. 5, 481. 1867. Sparganium androcladum fluctuans Morong, Bull.
Torrey Club 15: 78. .1888. Sparganium fluctuans Robinson, Rhodora 7: 60. 1905.
Stem floating, slender, usually elongated; leaves rather narrow, 2"- 5 1/2" wide, slightly, if at all, keeled, cellular-reticulate; bracts much shorter than the leaves, dilated and somewhat scarious-margined near the base; inflorescence usually branched, the main axis with 2-4 staminate heads, the branches usually bearing 1 pistillate and 2 staminate heads; fruiting heads about 10" in diameter; nutlets brown, the body fusiform, sometimes constricted at the middle; stigma obliquely oblong.
In ponds and cold lakes, Maine to Connecticut and Minnesota. July-Sept.