C. BULLaTA UTRICULaTA, Bailey. Perigynium considerably smaller and more spreading, less shining; scales longer and sharper. (C. Olneyi, _Boott_.)--Providence, R. I. (_Olney_).

15. C. retrorsa, Schwein. Stout, 2--3 high; culm obtusely angled and smooth or nearly so; leaves broad and soft, roughish, much longer than the culm; spikes 3--5, approximate near the top of the culm or the lowest remote, all but the lowest 1 or 2 sessile, 1--2' long and very compactly flowered, erect or spreading; perigynium very thin and papery, much inflated, prominently nerved, strongly reflexed; scale very short and small.--Swamps, from Penn. northward; common.--In var. HaRTH, Gray, a common monstrous form, the spikes are more or less scattered and peduncled, loosely flowered, and the perigynium less reflexed or spreading.

[=][=] _Scales all rough-awned._

16. C. lurida, Wahl. Variable in size, mostly ranging from 1--3 high, stout; culm rather obtusely angled and smooth; leaves long and loose, rough; spikes 2--4, variously disposed, the 1 or 2 upper sessile, nearly erect or often drooping, very densely flowered; perigynium thin and turgid, often somewhat shining, rather lightly about 10-nerved, very long and slenderly beaked, ascending; staminate spike single, scales linear, half as long as the perigynium or more. (C. tentaculata, _Muhl._)--Swamps, N. Eng. to S. Ill., and southward; abundant eastward.

Very variable.--Var. GRaCILIS, Bailey. Plant more slender; spikes 2--3, very small and narrowly cylindrical (1' long or less, and 3" broad or less). Mts. of Vt., Penn., and Tenn.

Var. flaccida, Bailey. Lower, scarcely exceeding 12--15' in height; spikes 2--4, all sessile and approximate at the top of the culm, small and straight (1' long or less), dull brown or reddish-brown, loosely flowered and entirely lacking the dense and comose appearance of the type; perigynium very thin and much inflated, the body usually larger than in the type and more gradually contracted into the beak.--N. Y. to N. J.; apparently scarce.

C. LuRIDA LUPULNA, Bailey. Very like C. lurida, but the spikes usually all approximate or only the lowest separated, erect or spreading, all sessile, green or greenish, often curved; perigynium very long-beaked and ascending; staminate spike one, sessile or very nearly so, strongly resembling that of C. lupulina. (C. tentaculata, var.

altior, _Boott_.)--Ma.s.s., Conn., and N. Y.; little known. C. lupulina retrorsa is distinguished from this by its yellow or straw-colored more scattered spikes which are shorter and always straight, and the loose, larger and more inflated perigynia.

[*] 1.--[+] 4. _Pseudocyperae._

[++] _Spikes all erect or ascending._

17. C. Schweinitzi, Dewey. Soft but erect, 1--2 high, stoloniferous, yellowish-green and becoming straw-colored in drying; culm flattish and smooth; leaves broad (3--4"), the radical longer than the culm, the others mostly short; spikes 3--4, the lower one or two short-peduncled, narrowly long-cylindrical (1--3' long, 4" broad); perigynium thin and somewhat inflated, prominently few-nerved, the long beak short-toothed, ascending; scale awned and commonly rough at the tip, a little shorter than the perigynium.--Swamps, W. New Eng. to N. J., and west to Mich.; local.

[++][++] _Spikes widely spreading or drooping._

18. C. hystricna, Muhl. Slender but erect, 1--2 high; culm very sharply angled and rough, at least above; leaves rather narrow, roughish; spikes 1--3, borne near the top of the culm, the upper one often sessile, the remainder on more or less filiform stalks, short (rarely 1' long) and compactly flowered; perigynium greenish, very strongly 15--20-nerved, the very slender beak strongly toothed; scale linear and rough-awned, nearly or quite as long as the perigynium.--Swales, throughout; frequent. Often confounded with n. 16.

Var. Dudleyi, Bailey. Taller; spikes larger and slimmer (1--2' long), light straw-colored, all secund and widely divaricate or nodding; perigynium stronger toothed; scales usually more prominent.--Swales, Conn. (_Wright_), Ithaca, N. Y. (_Dudley_), Wisc. (_Lapham_).

19. C. Pseudo-Cyperus, L. Tall and stout, 2--3 high; culm thick and very sharply triangular, rough throughout; leaves very long, rough-margined; spikes 3--5, all slenderly peduncled and more or less drooping, all somewhat contiguous, long (mostly 2--3') and narrowly cylindrical, very compactly flowered; perigynium elliptic-lanceolate, more or less 2-edged, many-costate, the beak shorter than the body, with erect short teeth, strongly reflexed; scale very rough-awned, about the length of the perigynium.--Swamps and lake-borders, N. Eng. to Penn., and Mich.; rare. (Eu.)

Var. Americana, Hochst. Mostly stouter, the leaves broader (about '); spikes thicker and commonly more drooping; perigynium longer, the beak mostly longer than the body and the teeth long and prominently spreading. (C. comosa, _Boott_.)--Swamps; common.

[*] 1.--[+] 5. _Squarrsae._

20. C. stenolepis, 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--1' 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. squarrsa, 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. TRACHYCHLaeNae.--[+] 1. _Shortianae._

22. C. Shortiana, Dewey. Tall and slender but strict, in small clumps, 2--3 high; leaves about ' 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. _Anomalae._

23. C. scabrata, 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. _Hirtae._

24. C. vestta, 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. striata, Michx., var. brevis, Bailey. Stiff, 1--2 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 1' 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 as long as the perigynium.--Pine-barren swamps, N. J., and southward; local.

26. C. Houghtnii, Torr. Stiff, 1--2 high, extensively creeping; culm rather sharply angled, rough, exceeding the leaves; leaves flat and very sharp-pointed; spikes 1--3, sessile or the lowest short-stalked, erect, varying from nearly globular to cylindric (1' long), compact; perigynium short-ovate, stiffly p.u.b.escent, prominently nerved and toothed; scale thin-margined, acute or awned, shorter than the perigynium.--Sandy knolls and banks from Maine to Minn. along our northern borders, and northwestward; rather local.

27. C. filiformis, L. Tall and very slender but erect, 2--3 high; culm obtuse, smooth; leaves very long, involute-filiform, rough; spikes 1--3, sessile, somewhat scattered, erect, short and thick (rarely over 1'

long); perigynium very short-ovate, the teeth very short, the few nerves obscured by the dense stiff hairs; scale thin and blunt, about as long as the perigynium.--Bogs, throughout, north of Penn.; frequent. (Eu.)

Var. latiflia, Boeckl. Culm mostly rough above; leaves flat, 1--2"

broad; spikes usually somewhat slimmer and scales often sharper and longer. (C. lanuginosa, _Michx._)--Swales and low meadows, throughout; common.

C. HiRTA, L. Variable in size (--2 high), widely creeping; culm rather slender but erect, obtuse and smooth or slightly rough above; leaves soft and flat, generally spa.r.s.ely hairy and the sheaths very hirsute, rarely smooth; spikes 2--3, distant, more or less shortly-peduncled, erect or nearly so, 1' long or less and rather loose; perigynium long-ovate, nerved, soft-hairy, the prominent beak slenderly toothed; scale thin and green-nerved, awned, mostly a little shorter.--E. Ma.s.s. to central N. Y. and Penn. (Nat. from Eu.)

[*] 2.--[+] 4. _Paludsae._

[++] _Teeth slender, mostly spreading._

28. C. trichocarpa, Muhl. Stout and tall, 2--3 high; culm sharply angled, rough above; leaves very numerous, flat and very rough, but not hairy, much exceeding the culm; spikes 2--5, scattered, the lower stalked and more or less spreading, long and heavy (1--4') but loosely flowered at base; perigynium long-ovate, many-costate, spa.r.s.ely short-hairy, about twice as long as the membranaceous, acute or ac.u.minate scale.--Marshes; frequent.--Var. IMBeRBIS, Gray. Mostly smaller throughout; perigynium smooth; scales usually sharper and longer. Drier places, N. Y. to Mo.; infrequent.

Var. Deweyi, Bailey. Leaves narrower, often becoming somewhat involute, smoother; spikes short (seldom over 1' long), all but the lowest one sessile; perigynium smooth, thick in texture, becoming polished with age, the nerves impressed; scales sharp, mostly a little shorter than the perigynium.--Dakota (_Seymour_), and northwestward. Resembles small forms of n. 29.

Var. aristata, Bailey. Mostly stouter; leaves more or less hairy on the under surface and sheaths; perigynium usually longer, smooth, the teeth longer and more spreading. (C. aristata, _R. Br._)--N. Eng. to Minn.; rare eastward.

[++][++] _Teeth short, erect or very nearly so._

29. C. riparia, W. Curtis. Very large and stout, 2--4 high, stoloniferous; leaves mostly broad, flat, rough, glaucous, much longer than the sharply angled culm; spikes 2--4, scattered and all more or less peduncled, the lowest often very long-stalked, varying from almost globular in starved plants to 3--4' long, erect or the lower somewhat drooping, loosely flowered below; perigynium ovate-lanceolate, coriaceous, rather lightly many-nerved, becoming polished, the beak short and thick; scale varying from blunt to awned, shorter or longer than the perigynium.--Swales; common. (Eu.)

C. ACUTIFoRMIS, Ehrh. Stout, 2--3 high; culm thick and sharp, mostly smooth; leaves broad, flat and glaucous, much prolonged; spikes 3--5, all but the uppermost peduncled, spreading or drooping, narrowly cylindric (2--3' long), loosely flowered below; perigynium ovate, very strongly many-nerved, the short beak slightly toothed; scale rough-awned and longer than the perigynium. (C. paludosa, _Gooden_.)--Swales, Dorchester, and New Bedford, Ma.s.s. (Nat. from Eu.) The former station has been recently destroyed.

[*] 3. MICRORHYNCHae.--[+] 1. _Atratae._

[++] _Alpine; plant small._

30. C. alpna, Swartz. Small and slender, --2 high; culm thin and obtuse, smooth or roughish, naked above; leaves narrow and flat, shorter than the culm; spikes commonly 3, sometimes 2 or 4, aggregated, globular and very small, all closely sessile or rarely the lowest exceedingly short-stalked; perigynium orbicular or obovate, nerveless or nearly so, the short beak slightly notched, a little longer than the ovate and black mostly obtuse scale.--Isle Royale, L. Superior. (Eu.)

31. C. atrata, L., var. ovata, Boott. Very slender but erect, 1--2 high; culm rather sharp, roughish above; leaves narrow but flat, shorter than the culm; spikes 3--5, all but the terminal one on slender stalks --2' long, drooping when mature, 1' long or less, ovate-oblong or short-cylindric, reddish-brown; perigynium broadly ovate, thin and puncticulate, very short-beaked, the orifice slightly notched; scale blunt, thin-margined, about as long as the perigynium. (C. atrata, _Man._)--White Mountains, N. H., Smugglers' Notch, Vt. (_Brainerd_), and northward.

[++][++] _Paludose; plant larger._

32. C. fusca, All. Rather slender but stiff, 1--3 high; culm sharp, roughish above; leaves very narrow, rough, mostly shorter than the culm; spikes 2--4, the terminal rarely all staminate, all sessile and approximate or the lowest sometimes very short-stalked, varying from globular to narrowly cylindric (often becoming 1' long), dark brown or variegated; perigynium elliptic and beakless, whitish and granular, nearly nerveless, the orifice entire; staminate scales very long-lanceolate, the pistillate lance-ovate and very sharp, conspicuously longer than the perigynium. (C. Buxbaumii, _Wahl._)--Bogs, throughout; frequent. (Eu.)

[*] 3.--[+] 2. _Rigidae._

33. C. vulgaris, Fries. Low and stiff, about 1 or sometimes 18' high; culm sharp, smooth or rather rough above; leaves narrow and stiff, shorter than the culm, glaucous blue; staminate spike sessile or nearly so; spikes 2--4, all sessile or rarely the lowest very short-stalked, short and erect (1' long or less), very densely flowered or sometimes becoming loose below, the lowest subtended by a bract 1--3' long; perigynium appressed, oval or round-ovate, mostly finely striate toward the base, the beak entire or very nearly so, bright green until over-mature; scale ovate and very obtuse, purple with a faint white nerve, conspicuously narrower and shorter than the perigynium, thus causing the spike in the growing plant to a.s.sume a characteristic green-and-black appearance.--Swales and low meadows along the sea-board, from Ma.s.s. northward; common. (Eu.)

Var. strictiformis, Bailey. Taller (1--2 high) and looser; culms slender; leaves long and narrow, lax, scarcely glaucous; staminate spike longer peduncled; pistillate spikes looser and often longer, mostly brown or tawny-green. (C. limula, _Man._)--Swales from E. Penn.

northward, near the seaboard; frequent. Often confounded with n. 34, but easily distinguished by the non-cespitose habit, sheaths not fibrillose, and the short scales very obtuse.

Var. hyperbrea, Boott. Somewhat stoloniferous, low, often smaller than the type; spikes shorter and mostly loosely flowered, often becoming very thin; scales generally longer, giving the spikes a darker color; stigmas often 3. (C. rigida, var. (?) Bigelovii, _Tuckerm._)--Alpine summits of N. H., Vt., and N. Y. (Eu.)

[*] 3.--[+] 3. _Acutae._