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 scoparia Schk.: Willd. Sp. PI. 4: 2.30. 1805.
Culms slender, erect, roughish above, 1/2°-2 1/2° tall. Leaves less than 1 1/2" wide, those of sterile shoots not very numerous, erect or ascending; lower bract bristle-form or wanting; spikes 3-10, oblong, narrowed at both ends, brownish or straw-colored, 3"-8" long, 2"-3" in diameter, densely many-flowered, varying from closely aggregated to scattered; staminate flowers basal; perigynia lanceolate, very thin, ascending or erect, 2"-3 1/4" long, rather less than 1" wide, the tips appressed, narrowly wing-margined, several-nerved on both faces, tapering into the serrulate 2-toothed beak; scales thin, brown, acute or acuminate, shorter than the perigynia; achenes 1/2" long; stigmas 2.
In moist soil, Newfoundland to Washington, Florida and Colorado. Ascends to 6200 ft. in North Carolina. July-Sept.
Carex tribuloides Wahl. Kongl. Vet. Acad. Handl. (II.) 24:
Bright green, culms usually stout, erect, roughish above, l'-3 1/2° tall. Leaves flat, 1 1/2"-4" wide, shorter than or the uppermost overtopping the culm, those of sterile culms very numerous, widely spreading, the sheaths loose; lower bract bristle-form, sometimes elongated; spikes 6-20, generally obovoid or top-shaped, but varying to suborbicular, blunt, densely clustered or sometimes separated, 3 1/2"-6" long, 3"-4" thick; staminate flowers basal; perigynia lanceolate, thin, sometimes distended over achene, greenish brown, flat, ascending or erect, the tips not spreading or recurved, 1 3/4-2 1/2" long, about 3/4" wide, several-nerved on each face, with a sharply 2-toothed, rough wing-margined beak; scales lanceolate, straw-colored, acute, about half as long as the perigynia; achenes short-oblong, 3/4" long; stigmas 2.
In meadows. New Brunswick to Saskatchewan, Florida and Arizona. Ascends to 2500 ft. in Virginia. July-Sept.
Carts cristata Schwein. Ann. Lye. N. Y. 1: 66. 1824.
Not Clairv. 1811. Carex tribuloidcs var. cristata Bailey, Proc. Am. Acad.
22: 148. 1886. Carex cristatella Britton; Brit. & Br. 111. Fl. 1: 357. 1896.
Culms rather stout, 10_3° tall, stiff, erect, roughish above, longer than the leaves. Leaves 1 1/2"-3 1/2" wide, those of sterile shoots numerous, spreading, the sheaths loose; lower bracts bristle-form, 1/4'-l 1/2' long; heads 6-15, globose or subglobose, 2"-4" in diameter, all densely aggregated into an oblong head 1' long or more or the lower slightly separated; staminate flowers basal; perigynia rather broadly lanceolate, distended over achene, spreading or ascending, squar-rose when mature, green or greenish brown, 1 1/2"-2" long, 3/4" wide, narrowly wing-margined, several-nerved on both faces, tapering into a serrulate 2-toothed beak; scales lanceolate, straw-colored, much shorter than the perigynia; achenes 3/4" long.