CYPERACE^S. (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.) 



-. -w. Heads short-oblong or globular, the spikes all aggregated, or only the lowest 



one or two separate. 

 = Plant very stiff throughout. 



112. C. Muhlenb6rgii, 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. ENERVIS, 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. ceph.al6ph.ora, Muhl. Mostly smaller and stricter, pale ; leaves 

 half as wide or less ; head small, rarely \ f 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. angustif 61ia, Boott. Low, 8' high or less ; leaves very narrow ; head 

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



rare. 



* 11. - 6. Dibicce. 



Perigynium nerveless or very nearly so. 



115. C. capitata, 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.) 



w. -t-t- Perigynium prominently nerved. 



116. C. gyn6crates, Wormsk. Stiff but very slender, 3-6' high, dice 

 cious ; leaves filiform and setaceous, about the length of the culm ; spike ob. 

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

 spreading or reflexed at maturity, 1 or 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 



