[=] Plant very stiff throughout.
112. C. Muhlenbérgii, Schkuhr. Pale, growing in small tufts, 1–2½° high; culms much prolonged beyond the few narrow and at length involute leaves; head {3/4}´ long or less, the individual spikes clearly defined; spikes globular, 4–8; perigynium nearly circular, very strongly nerved on both faces, broader than the rough-cuspidate scale and about as long.—Open sterile soils; frequent.—Var. enérvis, Boott. Perigynium nearly or entirely nerveless. Southeastern N. Y., and southward; rare.
[=][=] Plant strict but not stiff.
113. C. cephaloídea, Dewey. Lax, very green, 2–3° high; leaves broad (2–3´´) and thin, shorter than the long culm; head rather loose, ¾´ long or more, all but the very uppermost spikes clearly defined; perigynium ovate, entirely nerveless, long rough-pointed, spreading, twice longer than the very thin scale or more.—Shady banks, W. Mass. to Mich.; frequent.
114. C. cephalóphora, Muhl. Mostly smaller and stricter, pale; leaves half as wide or less; head small, rarely ½´ long, globular or very short-oblong, never interrupted, the lower 1 or 2 spikes usually bearing a very setaceous short bract; perigynium twice smaller than in the last, scarcely longer than the rough-cuspidate scale.—Dry and mostly sterile knolls; common.
Var. angustifòlia, Boott. Low, 8´ high or less; leaves very narrow; head smaller, usually tawny; perigynium mostly broader.—West and southward; rare.
[*] 11.—[+] 6. Diòicæ.
[++] Perigynium nerveless or very nearly so.
115. C. capitàta, L. Rigid, 3´–1° high; leaves filiform, shorter than the culm; head globular, uniformly staminate above, brown, very small; perigynium broadly ovate, very thin, whitish, prominently beaked, erect and appressed, longer than the very thin and obtuse scale.—Alpine summits of the White Mountains. (Eu.)
[++][++] Perigynium prominently nerved.