Perigynia barely 4 mm. long, each with a long 2-toothed beak. 
Perigynia 5-6 mm. long, each with a short entire or nearly entire 
beak. 
Leaf-blades scabrous: perigynia ovoid, somewhat longer than the scales. 
Leaf-blades pubescent: perigynia oblong or elliptic, about twice as long as 
the scales. 
A single species 
XXV. PHYSOCEPHALAE. 
in our range. 
A single species in our range. 
XXVII. PHYLLOSTACHYAE. 
CYPERACEAE 
XXIV. TRIQUETRAE. 
XXVI. SCIRPINAE. 
Body of the perigynium oblong; beak flattened. 
Body of the perigynium globose; beak subulate. 
XXVIII. LEPTOCEPHALAE. 
A single species in our range. 
A single species 
Spikes crowded into an oblong panicle: beak of the perigynium as long as 
in our range. 
the body to twice as long. 
Spikes in a large branching panicle: beak of the perigynium 2-3 times as 
long as the body. 
XXIX. FILIFOLIAE. 
XXX. VULPINAE. 
XXXI. MULTIFLORAE. 
Spikes very numerous in branched decompound clusters, small. 
Spikes several or many in narrow simple or slightly compound clusters. 
Seales acuminate, cuspidate or awned. 
Perigynia 3-5 mm. long. 
Perigynia 2-3 mm. long. 
Leaves as long as the stem or longer: perigynia dull yellow to 
brown. 
Perigynia ovate, nerveless or faintly 1-3-nerved, 1.5 mm. long. 
Perigynia nearly orbicular, delicately nerved, fully 2 mm. long. 
Leaves shorter than the stem: perigynia bright yellow. 
Seales blunt, scarious-tipped. 
reflexed. 
XXXII. MUHLENBERGIANAE. 
Spikes separated or the upper approximate: perigynia mostly radiating or 
Leaf-blades 1-3 mm. wide. 
Perigynia ovate-lanceolate or oblong-lanceolate, 2-3 mm. long. 
Perigynia stellately radiating or ascending. 
Perigynia radiately spreading, mostly over 3 mm. long, gradually 
Perigynia ascending, mostly less than 3 mm. long, each abruptly 
narrowed to the apex. 
narrowed into a beak. 
Perigynia reflexed, at least when mature. 
Perigynia narrowly lanceolate, 3-4 mm. long. 
Leaf-blades 5-9 mm. wide. 
Spikes allaggregated or the lower separated: perigynia spreading or as- 
cending. 
Perigynia 2 mm. long or shorter, nerveless or faintly few-nerved. 
Leaf-blades 2-3 mm. wide: perigynia ovate. 
Leaf-blades 1-2 mm. wide: perigynia orbicular-ovate. 
Perigynia 3 mm. long, strongly nerved or nerveless. 
Braets very short. 
Bracts foliaceous, much exceeding the spikes. 
XXXIII. ELONGATAE. 
Perigynia radiately spreading or reflexed when mature, 
Perigynium distinctly nerved on both faces; beak rough. 
Perigynium lanceolate: beak more than 14 as long as the body. 
Perigynium ovate: beak about 34 as long as the body, abrupt. 
Perigynium faintly nerved only on the outer face; beak smoothish. 
Perigynia appressed or ascending, at least not radiating. 
Perigynia oval to ovate-oval, about 2 mm. long. 
Perigynia linear-lanceolate, 4-5 mm. long. 
A. Perigynia much longer than broad. 
Perigynia lanceolate or ovate-lanceolate, 2-5 times as long as wide. 
Spikes green-brown, blunt. 
Spikes bright brown, pointed. 
Perigynia ovate, or if narrower not more than twice as long as wide. 
XXXIV. OVALES. 
a. Perigynia spreading or ascending. 
Spikes longer than thick, narrowed at the base: perigynia ascend- 
ing, slightly longer than the scales. 
Spikes as thick as long or shorter, rounded at the base: perigynia T 
spreading, much longer than the scales. 
205 
. C. umbellata. 
78. C. planostachys. 
. €. Chapmanii. 
80. C. dasycarpa. 
[os] 
-1 
89. 
> O Frasert. 
. C. picta. 
C. Willdenovii. 
. C. Jamesi, 
. C. leptalea. 
. C. filifolia. 
. C. stipata. 
88. 
C. Crus- Corvi. 
C. decomposita. 
. €. gravida. 
. C. vulpinoidea. 
. € triangularis. 
. C. zanthocarpa. 
. €. Sartwellüi. 
D C. TORE. 
C. radiata. 
C. retroflexa. 
C. Texensis. 
C. sparganioides. 
C. cephalophora. 
. C. Leavenworthii. 
. C. Muhlenbergii. 
C. Arkansana. 
C. sterilis. 
. C. Atlantica. 
C. interior. 
. €. brunnescens. 
. C. bromoides. 
. C. tribuloides. 
. C. scoparia. 
C. straminea. 
2. C. mirabilis. 
