[++] Heads narrow, the spikes scattered (or often aggregated in C. muricata.)
[=] Perigynium almost terete.
109. C. tenélla, Schkuhr. Exceedingly slender, 6´–2° high, in tufts; leaves flat, soft, and weak, mostly shorter than the culm; spikes 1–3-flowered, or the terminal 4–6-flowered, all distinct and scattered on the upper part of the culm, the bracts obsolete or the lowest present and very short; perigynium elliptic-ovate, very plump, finely nerved, the minute beak entire, longer than the white scale, usually at length splitting and exposing the blackish achene.—Cold swamps, N. Eng. to Penn., and far westward; common. (Eu.)
[=][=] Perigynium flattish.
110. C. ròsea, Schkuhr. Always slender and weak, erect, 1–2½° high, exceeding the narrow leaves; spikes 5–8, 6–14-flowered, the upper 3–4 aggregated, the others 3–9´´ apart, the lowest usually with a setaceous bract; perigynium lance-ovate, thin and shining, nerveless, scarcely margined, rough on the edges above, perfectly squarrose, very green, about twice longer than the translucent white scale.—Rich woods, N. Eng. to Minn. and Neb.; frequent.—Var. radiàta, Dewey. Lower and much more slender, the culms sometimes almost capillary; spikes 2–5, scattered, 2–4-flowered; perigynium mostly narrower and more ascending. Open places and drier woods; common.
Var. Texénsis, Torr. Very slender but strict, 1° high or less; spikes 3–4, all contiguous or the lower ones approximate, 2–6-flowered; perigynium lanceolate, the base prominently spongy, smooth or nearly so, conspicuously divaricate.—Dry places, S. Ill. (Schneck), and southward.
Var. retrofléxa, Torr. Often rather stiff, 1–1½° high; spikes 4–8, the upper ones aggregated, the lower 1 or 2 separated and commonly subtended by a conspicuous bract, often brownish; perigynium ovate, smooth throughout, very prominently corky and swollen at the base, which is frequently contracted almost to a stipe, at maturity usually widely spreading or reflexed; scale brownish and sharp, at length deciduous. (C. retroflexa, Muhl.)—Copses, throughout; rare northward.
111. C. sparganioìdes, Muhl. Stouter, stiff; culm 2–3° high; leaves very broad (usually ¼´ or more) and flat, their sheaths conspicuously clothing the base of the culm; spikes 6–10, the 2 or 3 upper ones contiguous, the remainder entirely separate, very green, oblong or short-cylindric, the lowest often compound, all truncate at top; perigynium ovate, wing-margined, rough on the short beak, often obscurely nerved on the outer face, considerably longer than the rough-pointed scale.—Rich woods; frequent.
C. muricàta, L. Culm 1–2° high, rough, longer than the narrow leaves; spikes 5–10, variously disposed, but usually some of them scattered, frequently all aggregated, rarely tawny; perigynium heavy, ovate, thin and shining, nerveless, the long beak minutely rough, spreading, a little longer than the sharp green or brownish scale.—Dry fields, E. Mass., where it is common, and sparingly south and westward to Va. and Ohio. (Nat. from Eu.)
[++][++] Heads short-oblong or globular, the spikes all aggregated, or only the lowest one or two separate.