464 PROCEEDINGS OF THE AMERICAN ACADEMY. 
a ee in a flexuous spike: scales 
lanceolate : perigynia _ abruptly slen- 
de ee kee 12) C. tenera, var. Richii. 
C) © Seales blunt or at most sitatinks 
Spikelets gray-green or finally dull brown, with 
strongly appressed-ascending very firm perigynia 
3.5 to 4 (very rarely 4.5) mm. long 
(9) C. albolutescens. 
Spikelets straw-colored or ap aoe with spread- 
ing-ascending perigynia 4 to 5.5 mm. long. 
Spike of 5 to 10 mostly phe sthtete 
(16) C. festucacea. 
Spike of 3 to 6 approximate spikelets 
(16) C. festucacea, var. brevior. 
2. Tips of perigynia equalled by the subtending scales 
O Spike stiff and erect, or at ng with approximate spikelets. 
+ Spike whitish or gray-gre 
X Perigynia lance-ovate, 4 ne 4.8 mm. sied nerveless on the 
inner faces, golden-yellow at base. (20) C. xerantica. 
X &X Perigynia broad-ovate to suborbicular 
siping strongly ribbed the denith of the inner eee 
2 mm. broad 18) C. foenea. 
Perey ouvies 6 or fsintly aeved: on the inner faces, 
(9) C. albolutescens. 
++ mee bronze 0 or ie uatiaes 
rigynia distinctly concave on the usually oo inner 
ces: achene 1 mm. broad .. . (19) C. leporina. 
& “actegge flat or convex on the siantly nerveless inner 
fac plump: achene 2 mm. broad . (22) C. adusta. 
O O Spike Psat Ph at least the lowest pie remote. 
+P yi sia nerveless or only faintly short-nerved on the inner 
fac 
Perieynin ovate-lanceolate, one-third as broad as lon 
achene 1 mm. broad eo 49) ©. praticla 
rire ovate, half as oud as lone: cal 1.5 mm. 
road . (21) C. aened. 
++ fetes distinetly evel on nike inner faces, 
o 4.4 mm. long, at most 2.4 mm. broad, 7- to 
13-ribbed on the inner faces, abruptly beaked. 
Spike of 4 ay 9 spikelets 6 to 10 mm. se perigynia 2. 8 
to 4 mm. long (28) Cpe 
Spike of rs to 15 scthelets 10 - 171 mm. lone: rigynia 
5to44mm.long . . . (18) ears var. perplera 
x X Perigynia 4 to 5.3 mm. long, 2.5 to 3 mm. broad, 3- 
nerved on the inner faces, obscurely ‘ead peaked 
S > es ra 
++ ++ Bracts leaf-like and much prolonged, the lowest 1 to 2d 
spikelets crowded: perigynia subulate . (23) C. Spalnsosplale 
