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..
Characters of the family. [Greek, referring to the ribbon-like leaves.]
About 22 species, of temperate and cold regions. Besides the following, 3 others occur in western North America. Type species: Sparganium erectum L.
Achenes broadly obovoid or cuneate-obpyramidal, sessile, distinctly beaked; inflorescence com-
pound; fruiting heads i0"-i5" in diameter.
Achenes fusiform (in S. minimum somewhat obovoid, but short-beaked and short-stipitate).
Stipe and beak of the achene each 1" long or more; fruiting heads 7 1/2" in diameter or more; anthers 3-4 times as long as broad.
Beaks straight or slightly curved; stigmas linear.
Heads all axillary; beak shorter than the body of the achene; leaves keeled.
Achenes dull; stigmas 1" long or less.
Inflorescence branched, the branches geniculate, bearing 3-7 staminate heads.
Inflorescence simple, or, if branched, the branches strict and bearing 0-2 stami-
Achenes glossy; stigmas 1 1/4"- 1 3/4" long-
Heads, at least some of them, supra-axillary.
Leaves, at least the middle ones, strongly triangular-keeled; stem usually erect, strict.
Fruiting heads over 10" in diameter; leaves broad; bracts ascending-spreading; beak fully as long as the body of the achene.
Leaves 3 1/2"-7 1/2" wide, strongly veined; fruiting heads about 15" in diameter; achenes brown, shining, each gradually tapering into the beak.
Leaves 1 1/2"-4" wide, weakly veined; fruiting heads 10"-12l/2" in diameter; achenes green, dull, each abruptly contracted into the beak.
Fruiting heads rarely 10" in diameter; leaves narrow; bracts almost erect.
Heads distant, nearly 10" in diameter; achenes grayish-brown, distinctly
S. diversi folium.
Heads approximate, about 7 1/2" in diameter; achenes dark olive-brown, not
Leaves not keeled, or only slightly so, narrow and slender; stem weak and often floating; beak decidedly shorter than the body of the achene.
Leaves usually 2 1/2-5" wide; leaves and bracts conspicuously scarious-margined; fruiting heads 8 1/2"-10" in diameter; achenes gradually beaked.
Leaves 1 1/2"-2" wide; leaves and bracts not conspicuously scarious-margined; fruiting heads about 7 1/2" in diameter; achenes abruptly beaked.
♦Text revised by Dr. John Kunkel Small.
Beaks gladiate-curved; stigma short oblong.
Stipe and beak of the achene short or none, always less than 1/2" long; fruiting heads about 5" in diameter; stigmas oblong; anthers 1 1/2-2. times as long as broad.
Heads all sessile, or the lowest short-pedicelled, axillary; the staminate head distant from
the pistillate ones; achenes short-beaked.
Lower pistillate heads distinctly pedicelled and supra-axillary; the staminate head close to
the upper pistillate one.