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..
Culms slender, 1°-3° high, very rough below inflorescence, reddened and filamentose at base, the plant stoloniferous. Leaves 1" wide, flat, shorter than or exceeding culm, little if at all nodulose; lower bracts narrow, exceeding culm; staminate spikes usually 2, slender-stalked; pistillate spikes 1-3, narrowly cylindric, 7"-24" long, 2 1/2" wide, short-peduncled, loosely flowered at base; perigynia somewhat inflated, oblong-ovoid, yellowish-green, strongly several-nerved, 21/2"-3" long, abruptly contracted into a slender bidentate beak; scales lanceolate, sharply acuminate, narrower and somewhat shorter than perigynia; stigmas 3.
On lake and river shores, Maine to Quebec, west to Athabasca. Local. Intergrades with the next. Summer.
1889. C. vesicaria vars. monile and jejuna Fernald, Rhodora 3:
Glabrous, culm slender, erect, 1 1/2°-3° tall, not spongy at base, generally acutely angled and very rough above. Leaves elongated, 1 1/2-3" wide, sometimes exceeding the culm, little nodulose; bracts similar, often overtopping the culm; staminate spikes 1-4, usually 2 or 3, slender-stalked, commonly subtended by short bracts; pistillate spikes 1-3, erect-spreading, cylindric, 1'-3' long, about 3i" in diameter, many-flowered with perigynia in several rows, rather loose at maturity, the upper sessile, the lower more or less slender-stalked and remote; perigynia yellowish-green, ascending, globose-ovoid, inflated, 2 1/2"-4' long, rather strongly 8-10-nerved, abruptly contracted into a slender 2-toothed beak; scales lanceolate, acuminate or awned, shorter than perigynia; stigmas 3.
Carex vesicaria L. Sp. PI. 979. 1753. Carex Vaseyi Dewey, Am. Journ. Sci. (II.) 29: 347. 1860.
Glabrous, culm slender, erect, 1°-3° tall, not spongy at base, generally acutely angled and very rough above. Leaves elongated, 1 1/2" - 3" wide, about equalling the culm, little nodulose; bracts similar, about equalling the culm; staminate spikes 2-4, slender-stalked, commonly subtended by short bracts; pistillate spikes 1-3, usually 2, erect, sile or short-peduncled, oblong-cylindric, 1'-2 1/2' long, 4 1/2"-7 1/2" thick, closely many-flowered, the perigynia in several rows; perigynia yellowisli-green, ascending, ovoid, inflated, 3 "-4" long, rather strongly 8-10-nerved, contracted into a slender 2-toothed beak; scales ovate, acute or acuminate, narrower and shorter than perigynia; stigmas 3.
Quebec to British Columbia, south to Pennsylvania and Ohio. Also in Europe, Asia and north Africa. June-Aug.