483 
* Staminate flowers borne at the apex of the spikes.— ACROARRHEN &, 
+ Perigynium thick in texture and spongy at the base, mostly stipitate, conspicnously 
nerved: inflorescense in No. 30 nearly a panicle. 
30. C. crus-corvi Shuttlw. Very stout, 7.5 to 10 dm. high, glaucous, leaves flat 
and very wide: head much bracted and compound, 6 to 15 cm. long: perigynium 
long-lanceolate, the short cushion-like base very thick, the roughish and very 
slender beak thrice the length of the body, and three to four times the length of the 
inconspicuous scale, (C, Nuttallii Olney, Hall’s Pl. Tex., No. 833.)—Bogs, Minnesota 
to Florida and Texas. 
31. C, stipata Muhl. Stout, 3to&8dm. high, green, in clumps, the culm rather 
soft and very sharply angled: head 2 to 6 em. long, rarely somewhat compound at 
base, interrupted, the lowest spikes of 1.5 em. long: perigynium lanceolate, brown- 
nerved, the beak toothed and slightly rough, about twice the length of the body and 
much longer than the scale.—Swales, Canada to our eastern limits. 
++ Perigynium mostly very small and short and nearly nerveless (in ours), not spongy at 
the base: head yellow or tawny, mostly long. 
32. C. triangularis Bock]. Stiff and erect, 3 to 7.5 dm. high, the narrow leaves 
mostly shorter than the culm: head 2 to 5 em. long and usually interrupted below, 
simple, dull tawny-brown at maturity: spikes short-oblong and truncate at the 
apex, the perigynia conspicuously spreading: bracts few and inconspicuous, or 
absent above the base of the head: perigynium broadly ovate or round-ovate, minutely 
nerved and often slightly dotted. (C. vulpinoidea, var. platycarpa Olney, Hall’s PI. 
Tex., No. 729. Var. Drummondiana Boockl.)—Wetsplaces and prairies, Mississippi to 
Indian Territory and central Texas. 
+ + + Perigynium mostly short-ovate, mostly glossy at maturity, often nerred, not spongy 
at the base (eccept in Nos. 33 and 34): head green or nearly so when mature (light 
tawny in Nos. 34.and 35), mostly short. 
++ Head loose and very slender: perigyniwm spongy at base. 
33. C. Texensis. Very slender, 2 to 4 dm. high, the leaves loose and mostly very 
narrow: head 1.5 to 3 em. long, open below, green: perigynium lanceolate, smooth 
or nearly so, spreading at right angles to the rachis. (C. rosea, var. Texensis Torr. )— 
Dry places, southern Illinois to Alabama and Texas. <A delicate and pretty species, 
34. C. retroflexa Muhl. Slender but rather stiff, 3 to 5 em. high: head much as 
in the last but tawny: perigynium ovate, smooth, very corky at the base, which is 
contracted until almost stipitate, at full maturity widely spreading or even reflexed : 
scale brownish and sharp, at length deciduous. (C. rosea, var. retroflera Torr.)— 
Throughout the States east of the Mississippi and in Indian ‘Territory and central 
Texas. 
++ ++ Head dense and stout: perigynium not spongy at base. 
35, C. Leavenworthii Dewey. Low (15 to 25 cm. high) but erect, the culms 
mnostly overtopping the very narrow long-pointed leaves: head globular or globu- 
lar-oblong and very small, tawny: perigynium very small, ovate and beaked, entire, 
rather thin, the edges rounded, about the leneth of or a little shorter than the thin 
acute scale. (C. cephalophora, var. angustifolia Boott. C. cephalophora Olney, Hall’s 
Pl. Tex., No. 732.)—Grassy places, Ontario to Texas. Nearer the C. rosea group than 
to C. cephalophora. 
36, C. cephalophora Muhl. Slender but mostly strict, 3 to 5 cm. high, pale: head 
small (rarely exceeding 1.5 em.) but rather broad, especially at the base, and very 
dense, never interrupted, green, the lower one or two spikes of the head bearing a 
very setaceous short bract: perigynium twice larger than in the last, green and 
