[*] 1.—[+] 5. Squarròsæ.
20. C. stenólepis, Torr. Stout and very leafy, 1–2° high; culm obtusely angled, very smooth; leaves about 3´´ broad, rough on the nerves, the upper and the bracts very much longer than the culm; terminal spike often pistillate at top; other spikes 3–5, the uppermost sessile on the zigzag rhachis, short (1–1½´ or less) and evenly cylindrical, often staminate at top; perigynium very abruptly contracted into a short but slender toothed beak, shorter than the long-linear and rough scale.—Swamps and meadows, central Penn., to N. Ohio, west and southward; frequent.
21. C. squarròsa, L. Cespitose, 2–3° high; culm sharply angled, more or less rough above; leaves broad and weak, roughish, exceeding the culm; bracts much less prominent than in the last; spikes 1–3, thick, the terminal always two-thirds pistillate or more, the remainder more or less stalked, erect or slightly nodding, globular or oblong-cylindric, brown, exceedingly densely flowered; perigynium larger, the beak rough; scale short and usually invisible.—Bogs, throughout; infrequent.
[*] 2. Trachychlænæ.—[+] 1. Shortiànæ.
22. C. Shortiàna, Dewey. Tall and slender but strict, in small clumps, 2–3° high; leaves about ¼´ broad, flat, rough on the nerves; spikes 3–5, somewhat approximate near the top of the culm, the lowest 2 or 3 short-peduncled, erect, small (1´ long or less, and 2´´ wide), evenly cylindrical, exceedingly densely flowered; perigynium small, circular or round-ovate, flat, sharp-edged, nerveless, the orifice entire, perfectly squarrose; scale thin and blunt, about the length of the perigynium.—Wet meadows, S. Penn. and Va. to Ill.; rare eastward.
[*] 2.—[+] 2. Anómalæ.
23. C. scabràta, Schwein. Tall and rather stout, very leafy, 1–3° high, culm sharply and very roughly angled; leaves broad and flat, very rough; spikes 3–5, scattered, the upper 1 or 2 sessile, the remainder often long-peduncled and sometimes nodding, 1–2´ long, narrowly cylindrical and compactly flowered; perigynium broadly ovate, prominently few-nerved, rough, the beak nearly as long as the body and slightly toothed; scale acute and rough-tipped, green-nerved, about as long as the body of the perigynium.—Wet meadows and glades, as far west as Mich.; common eastward.
[*] 2.—[+] 3. Hirtæ.
24. C. vestìta, Willd. Stout and stiff, 2–3° high; culm sharply angled, smooth or somewhat rough; leaves narrow and rather short, roughish; staminate spike 1, rarely 2, sessile or nearly so; pistillate spikes 2–5, approximate and sessile, or rarely the lowest sub-radical, often staminate at top, oblong or short-cylindric (rarely 1´ long), compactly flowered; perigynium ovate, nerved, stiffly hairy, short-beaked, the beak often purple, and white-hyaline at the orifice, which becomes more or less split with age; scale thin and blunt or acute, shorter than the perigynium.—Tufted in sandy soils, from N. Eng. to N. Y., and southward; frequent.
25. C. striàta, Michx., var. brèvis, Bailey. Stiff, 1½–2½° high; culm sharply angled, smooth or slightly rough above, mostly exceeding the leaves; leaves narrow and stiff, becoming involute; spikes 1–2, mostly closely sessile, considerably separated when two, short (rarely 1½´ long) and rather thick, erect; perigynium broad-ovate with impressed nerves, smooth, ascending, short-beaked and very short-toothed; scale thin, obtuse or acutish, mostly about ½ as long as the perigynium.—Pine-barren swamps, N. J., and southward; local.