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..
Carex bullata Schk.; Willd. Sp. PI. 4: 309. 1805.
Carex Olneyi Boott, 111. Car. 1: 15. 1858.
Carex Greenii Boeck. Flora 41: 649. 1858.
Glabrous, culms slender, erect, 1°-3 1/2° high, roughened above on the sharp angles. Leaves and bracts narrow and elongated, rather stiff, commonly overtopping the culm, rarely more than 2" wide, rough-margined, sparingly nodulose; staminate spikes mostly 2, long-stalked; pistillate spikes 1-3, usually 2, light green, varying from almost sessile to long-stalked and spreading, many-flowered, oblong to cylindric, 3/4'-2' long, .4 1/2"-9" in diameter; perigynia much inflated, strongly nerved, dull or shining, ovoid, 2 1/2"-4" long, ascending-spreading, contracted into a subulate rough 2-toothed beak, longer than the lanceolate acuminate to obtusish scale; stigmas 3.
In swamps, Maine to Georgia. June-Aug.
C. Tuckermani Dewey, Am. Journ. Sci. 49: 48. 1845.
Glabrous, culm very slender, roughened above on the angles, erect, 1 1/2°-3 1/2° tall. Leaves and bracts much elongated, commonly much overtopping the culm, 1 1/2"-2 1/2' wide, more or less nodulose; staminate spikes 2 or 3; pistillate spikes stout, cylindric, 1'-2' long, 6"-9" in diameter, the upper sessile or nearly so, the lower stalked and usually spreading; perigynia very much inflated and bladder-like, shining, broadly ovoid, prominently few-nerved, ascending, abruptly contracted into a smooth subulate 2-toothed beak; scales lanceolate, acute to short-cuspidate, less than half as long as the perigynia; achenes prominently excavated in middle; stigmas 3.
In bogs and meadows, New Brunswick to Minnesota, south to New Jersey, Indiana and Iowa. June-Aug.
C. retrorsa Schwein. Ann. Lye. N. Y. 1: 71. 1824. Carex Hartii Dewey, Am. Journ. Sci. (II.) 41: 226. 1866.
Glabrous, culm stout, erect, smooth or slightly rough above, 1°-3 1/2° tall. Leaves much elongated, thin, rough-margined, nodulose, 2 1/2"-5" wide, the upper commonly exceeding the culm, the bracts similar, usually very strongly overtopping the culm; staminate spikes 1-3, short-stalked; pistillate spikes 3-8, ascending or spreading, all close together at the summit and sessile or very nearly so, or the lowest distant and stalked, cylindric, densely many-flowered, 1'-3' long, 7"-10" in diameter; perigynia ovoid, membranous, strongly few-nerved, yellowish green, 3 1/2"-5" long, the lowest at least reflexed at maturity, tapering into a subulate 2-toothed beak; scales lanceolate, acute or acuminate, smooth, one-third to one-half as long as the perigynia; stigmas 3.