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 aggregata Mackenzie, Bull. Torr. Club 37: 246. 1910.
Culms slender, erect, triangular, rough beneath head only, 2° or less tall. Leaves 1 1/2"-2" wide, shorter than the culm; bracts bristle-form, elongated but shorter than the head; spikes numerous, androgynous, ovoid or subglobose, densely aggregated, even the lowest but slightly separate, the head I2"-i8" long, 5" thick; perigynia ascending or spreading, a little more than 1 1/2" long, the body ovate, 1" wide, nerved on outer, nerveless on inner face, tapering into a 2-toothed beak about length of body; scales ovate, hyaline with green midrib, acuminate to cuspidate, narrower than and about length of body of perigynia; stigmas 2.
Rather dark green with white and green mottled sheaths, culms stout or slender, rough above, sharply 3-angled, 1/2°-3° tall. Leaves broad and flat, 2 1/4"-5" wide, usually shorter than the culm, their lower part septate-nodulose as are the loose membranous transversely rugulose sheaths; spikes 6-12, deep green, oblong or subglobose, 2 1/2"- 4" in diameter, 15-50-flowered, the upper aggregated, the lower 2-4 commonly separated, the lower bracts developed; perigynia flat, ovate, 1 1/2" long, 1" wide, spreading or radiating, narrowly wing-margined to the rounded base, faintly few-nerved on the outer face, the rough 2-toothed beak one-half the length of the body; scales ovate, hyaline, acute or cuspidate, equalling body of perigynia; stigmas 2.
In woods and thickets, New Hampshire to Ontario and Michigan, south to Virginia, Kentucky and Kansas. Ascends to 2100 ft. in Virginia. June-Aug.
Carex cephalophora var. maxima Dewey, Am. Journ. Sci.
Light green, culms stout but soft, sharply 3-angled, flattened, narrowly winged, erect or reclining, 1 1/2°-3° long, roughish above. Leaves flat, 1 1/2"-4" wide, shorter than or exceeding the culm, the sheath band strongly reddish-dotted but not transversely rugulose; bracts almost filiform, commonly short; spikes androgynous, several or numerous (10 or fewer) in a compact or somewhat interrupted head V-2' long, 4"-5" thick; perigynia ovate or ovate-lanceolate, rounded at base, short-stipitate, 1 1/2"-2" long, green or at maturity, yellowish brown, faintly few-nerved on the outer side, the tapering rough 2-toothed beak nearly as long as the body; scales ovate, brownish-tinged, acuminate or short-awned, about as long as the perigynia; stigmas 2.
In meadows, Maine to Pennsylvania and Michigan. Local. June-July.