90. C. umbellàta, Schkuhr. (Pl. 6, fig. 11–14.) Low, growing in small and dense mats (1–3´ across); leaves short and often stiff (2–6´long), flat, the earliest very narrow but the later often 2´´ broad; spikes all on separate scapes which rarely exceed 1–2´ in length (or rarely one or two short true culms), usually densely aggregated at the surface of the ground and hidden by the leaves, the pistillate spikes green or tawny and rather loosely few-flowered; perigynium slenderly beaked, toothed, very lightly pubescent, about the length of the acute and often rough-tipped scale.—Dry banks and knolls, N. Eng. to N. J. and N. Y., and perhaps farther westward; infrequent.—Var. vícina, Dewey. Tufts looser and larger; leaves longer (often 1° or more) and laxer, sometimes broader; some pistillate spikes borne near the base of the staminate on a true culm which is 3–8´ high, one or two on each culm. With the species and farther westward; infrequent.
91. C. nìgro-marginàta, Schwein. Leaves mostly stiffer than in n. 90, often broader, and some of the culms prolonged; perigynium smooth or nearly so, shorter beaked; scales purple-margined, giving the spikes a very dark or variegated appearance, considerably larger and longer than in the last.—Dry hillsides, N. J., and southward; local.
[*] 7.—[+] 3. Triquétræ.
92. C. pubéscens, Muhl. Strict, 1–2° high, pubescent throughout; leaves flat and soft, shorter than the culm; spikes 2–4, the lower 1 or 2 short-peduncled, and about ½´ long, loosely flowered, erect; perigynium very hairy, conspicuously beaked and minutely toothed, straight, about the length of the truncate and rough-cuspidate thin scale.—Copses and moist meadows, N. Eng. to Ky., and westward; frequent.
[*] 8. Phyllostáchyæ.
93. C. Jamèsii, Schwein. (Pl. 5, fig. 17–21.) Diffuse, 6–10´ high; leaves very narrow (1´´ or less), much surpassing the culm; spike very small, the staminate portion inconspicuous, the pistillate flowers 1–3 and loosely disposed; perigynium globular, produced into a very long and roughened nearly entire beak; scale narrow, the lowest often 1–2´ long, the upper often shorter than the perigynium. (C. Steudelii, Kunth.)—Woods, N. Y. to Ill., and southward; frequent.
94. C. Willdenòvii, Schkuhr. Lower, stiffer, the leaves broader and pale; spike larger, the pistillate flowers 3–9, compact; perigynium bearing a prominent two-edged very rough beak; scales chaffy, nerved, as broad as and somewhat longer than the perigynium, or the lowest rarely overtopping the spike.—Copses, Mass. to Mich., and southward; rare.
95. C. Báckii, Boott. Forming dense mats; leaves still broader (2´´ or more), very abundant; staminate flowers about 3; pistillate 2–5; perigynium more gradually beaked, smooth throughout; scales very broad and leaf-like, all exceeding the culm and entirely enveloping the spike.—W. Mass. to Ohio, and far westward; local and rare, especially eastward.
[*] 9. Leptocéphalæ.
96. C. polytrichoìdes, Muhl. Capillary, erect or slightly diffuse, 6–18´ high; leaves mostly shorter than the culm; spike 2–4´´ long, linear, the staminate portion very small; perigynium thin and green, nerved, about twice longer than the obtuse caducous scale.—Bogs; common.