Sparganium emersum Rehmann

Sparganium multipedunculatum (Morong) Rydb. Bull
Torrey Club 32 : 598. 1905.
Sparganium simplex multipedunculaia Morong, Bull. Torrey Club 15 : 79. 1888. Sparganium subvaginatum Meinsh. Mel. Biol. Acad. St. Petersb. 13: 390, in part. 1893.
Perennial, with a creeping rootstock ; stem erect or sometimes floating, 3-5 dm. high, rarely only 1-2 dm. high; leaves 3-5 dm. long, 5-10 mm. (rarely 3-4 mm.) wide, of a firm texture, slightly keeled, dilated and scarious-margined towards the base, acute; bracts similar but still more dilated at the base ; inflorescence usually simple ; pistillate heads 2-5, the lower 1 or 2 decidedly peduncled, some of them supra-axillary ; staminate heads 3-5, usually distant from the pistillate ones, but close to each other, the uppermost usually confluent ; fruiting heads 1.5-2 cm. in diameter ; sepals distinctly clawed, the blades spatulate, erose at the apex ; achenes brown ; stipe 2-2.5 mm. long ; body fusiform, about 4 mm. long ; beak 2.5-3 mm. long; stigma linear, about 1 mm. long; anthers about 1 mm. long, about one third as broad.
Type locality : Great Falls, Montana.
Distribution : Ponds and marshes from British Columbia to California, Colorado, western Ontario, and Mackenzie.

Sparganium acaule (Beeby) Rydberg
Sparganium simplex acaule Beeby ; Macoun, Cat. Can. PI. 5 : 367. 1890. Sparganium diversifolium nanum Graebner, in Engler, Pflanzenreich 4 10 : 21. 1900. Sparganium nanum Fries ; Graebner, in Engler, Pflanzenreich 4 10 : 21, as synonym. 1900. Sparganium diversifolium acaule Fernald & Eames, Rhodora 9 : 88. 1907.
Perennial; stem erect, 1-3 dm. high, strict; leaves erect, triangular-keeled, 2~A dm. long, overtopping the stem, 2-4 mm. wide, cellular-reticulate ; bracts almost erect, similar to the leaves, but dilated and broadly scarious-margined at the base ; inflorescence simple ; pistillate heads 1-3, crowded, usually all sessile, supra-axillary, rarely the lowest shortstalked; staminate heads 2-4; fruiting heads about 1.5 cm. in diameter; sepals spatulate, erose at the apex, without distinction between blade and claw; achenes dark olive-brown, not nerved ; stipe 1-2 mm. long ; body fusiform, 3-4 mm. long, usually decidedly constricted at the middle ; beak 1.5-2 mm. long; stigma about 1 mm. long; anthers about 1 mm. long and one fourth as thick.
Type locality : Lake Verde, Prince Edward Island.
Distribution : Muddy shores and swamps, from Newfoundland to Virginia, Iowa, and South Dakota.

Sparganium chlorocarpum Rydberg, sp. nov
Perennial, with a creeping rootstockand numerous roots from the thickened portion at the base of the stem ; stem slender, 3-6 dm. high, sometimes floating ; leaves slender, 3-6 cm. long, 3-7 mm. wide, at least the middle ones keeled ; bracts similar, ascending, only slightly if at all dilated or scarious at the base ; inflorescence simple ; pistillate heads 2-4, all sessile or the lowest one peduncled, some of them supra-axillary ; staminate heads 3-7 ; fruiting heads 2-2.5 cm. in diameter ; sepals two thirds as long as the achenes, spatulate-erose at the apex, the blades gradually tapering into the claws ; achenes green, rather dull ; stipe about 2 mm. long; body fusiform, 4-5 mm. long; beak about 4 mm. long; stigma about 1.5 mm. long.
Type collected in Emmet County, Iowa, in September, 1898, Miss Alia Cratty (herb. N. Y, Bot. Gard.).
Distribution : Marshes and rivers, Western New York, Indiana, and Iowa.