CYPERACEiE. (sedge FAMILY.) 617 



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 onlij the lowest 



one or two separate. 



= Plant vert/ stiff throughout. 



112. C. Muhlenbergii, Schkuhr. Pale, growing in small tufts, 1 -2\° 

 high ; culms much prolonged beyond the few narrow and at length involute 

 leaves ; head f 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 ster- 

 ile soils; frequent. — Var. exervis, Boott. Perigynium nearly or entirely 

 nerveless. Southeastern N. Y., and southward ; rare. 



= = Plant strict but not stiff. 



113. C. cephaloidea, Dewey. Lax, very green, 2-3° high; leaves 

 broad (2-3'') and thin, shorter than the long culm ; head rather loose, f 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. cephalophora, Muhl. Mostly smaller and stricter, pale ; leaves 

 half as wide or less ; liead small, rarely ^' 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. angustifolia, Boott. Low, 8' high or less ; leaves very narrow ; head 

 smaller, usually tawny; perigynium mostly broader. — West and southward ; 



rare. 



* 11. — -t- 6, Dibicce. 



++ Perigynium nerveless or very nearly so. 

 il5. C. capit^ta, L. Rigid, 3'-l° high; leaves filiform, shorter than 

 the culm ; head globular, uniformly staminate above, brown, very small ; peri- 

 gynium broadly ovate, very thin, whitish, prominently beaked, erect and ap- 

 pressed, longer than the very thin and obtuse scale. — Alpine summits of the 

 White Mountains. (Eu.) 



++ •*-(■ Perigynium prominentl y nerved. 



116. C. gynocrates, Wormsk. Stiff but very slender, 3-6' high, dice 

 3ious ; leaves filiform and setaceous, about the lengtli of the culm ; spike ob 

 long, 2-4" long; perigynium elliptic-ovate, nearly terete, stipitate, widely 

 spreading or reflexed at maturity, 1 o" 2 sometimes borne at the base of the 

 staminate spike. — Cold sphagnum swamps, Penn., north and westward; local, 

 particularly southward. 



117. C. exilis, Dewey. Very stiff, slender, 1-2° high ; leaves involute- 

 filiform and very stiff, shorter than the culm; spike varying from almost 

 globular to cylindrical (frequently 1' long), either unisexual or the sexes vari- 

 ously placed, very rarely a supplementary spike at base ; perigynium elliptic- 

 ovate, flattish, stipitate and somewhat cordate at base, strongly brown-nerved 



