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..
Similar to the preceding species, but the leaves generally much broader, 2"-5" wide, the similar bracts much overtopping the culm; spikes 1-6, generally three, oblong-cylindric, very dense, the pistillate portion 1'-1 3/4' long, 4"-8" in diameter, often staminate at both ends, the terminal one commonly tapering to a conic summit; basal staminate flowers rather less numerous than in C. squarrosa; perigynia dull straw-color, obovoid, ascending or the lowest spreading or reflexed, inflated, truncatcly contracted into the slender 2-toothed beak, which is often upwardly bent; scales oblong-lanceolate, obtusish; achene obovoid, 1 1/4" long, sharply 3-angled with concave sides, tipped with the slender style.
Carex intumescens Rudge, Trans. Linn. Soc. 7: 97. pl. 9. f.
Glabrous, culms slender, commonly tufted, erect, 1 1/2°-3° high. Leaves elongated, dark green, shorter than or sometimes equalling the culm, roughish, 1 1/2"-3 1/2" wide, the sheath a little prolonged; bracts similar, overtopping the culm; staminate spike narrow, mostly long-stalked; pistillate spikes 2 (1-3), sessile or short-stalked, globular or nearly so; perigynia 1-12, spreading or the upper erect, 5"-10" long, much inflated, about 2 1/2' in diameter above the rounded base, many-nerved, contracted into a subulate 2-toothed beak, the teeth somewhat spreading at maturity; scales narrowly lanceolate, aristate, or obtuse in few-flowered northern plants, about one-half as long as the perigynia; stigmas 3.
In swamps, bogs and wet woods, Newfoundland to Manitoba, south to Florida and Louisiana. May-Oct.
Carex intumescens var. globularis A. Gray, Ann. Lye. N. Y.
3: 236. 1834. Not C. globularis L. 1753. Carex Grayi Carey, Am. Journ. Sci. (II.) 4: 22. 1847. Not
C. Grayana Dewey, 1834. Carex Grayi hispidula A. Gray; Bailey, Mem. Torr. Club
1: 54. 1889. Carex Asa-Grayi Bailey, Bull. Torr. Club 20: 427. 1893.
Glabrous, culms stout, erect, 2°-3° tall. Leaves elongated, dark green, 2 1/2"-4 1/2" wide, the upper commonly overtopping the culm, the sheath not prolonged; bracts similar to the upper leaves, usually much overtopping the culm, short-sheathing; staminate spike mostly long-stalked; pistillate spikes 1 or 2, globose, dense, about 1' in diameter; perigynia 6-30, 6"-9/' long, ovoid, glabrous or hispidulous, much inflated, many-ribbed, round-truncate at base, about 3 1/2" in diameter above the base, contracted into a sharp 2-toothed beak; scales ovate, obtuse to slightly cuspidate, scarious, about one-third as long as the perigynia; stigmas 3.