462 PROCEEDINGS OF THE AMERICAN ACADEMY. 
Culms taller: leaves broader: spikelets 8 to 11 mm. lon 
5) C. Crawfordii, var. vigens. 
X X Tips of perigynia equalled by the ovate bluntish glossy 
dark scales C’. oronensis. 
++ Perigynia brobder neaily or  Gulte half as bree as long. 
X Tips of perigynia distinctly exceeding the subtending 
scales. 
§ Leaves 2.5 mm. or more wide. 
C) Spikelets compactly flowered, the mature perigynia 
with recurved or spre Bice tips concealing the 
(8) C. cristata. 
OO dilate with ascending or slightly pvadiig peri- 
gynia; scales appar 
A Mature perigynia coleatak or pale straw- or in 
loose spikelets: spikes more than 2.2 cm. long 
(if shorter, with ask chestnut scales). 
Spikelets approximate in ovoid or oblong spikes. 
Scales pale, not strongly cas eget with the 
perigynia . C. Ss 
Scales dark Sioatinet, eerounly: cence 
the perigynia . . (10) C. mirabilis, var. yee 
Spikelets scattered in a moniliform spike 
(10) C. mirabilis, var. perlonga- 
A A Mature perigynia brown, in dense spikelets: spikes 
at most 2.2 cm. long: scales pale brown 
3 
(17) C. Bebbii. 
§ § Leaves narrower 
Spike stiff, with crowded closely flowered spikelets 
(17) ¢. Bebbit. 
Spike flexuous and moniliform, or at least with the 
loosely flowered spikelets scattered . (11) C. stramined. 
X & Tips of perigynia equalled by the subtending scales. 
Spike stiff and erect, or at least with the spikelets ap- 
proximate : 
Spike brown or ferrugineous . . . . (19) C. /eporina- 
Spike brownish white C. zerantica. 
§ § Spike flexuous, or at feast with ‘the lower spikelets 
remote. 
0 Perigynia nerveless or minutely short-nerved on the 
inner face 
Mature pécigynia straw-colored or pale brown, one- 
third as broad as lon (7) C. praticola. 
Mature ean olive- are or ‘Sehnte, one-half as 
broad as | 21) C. aenea. 
OO Perigynia are see ribs the fe length of the gre face: 
spike silvery green. . (18) C. foenea. 
d. 
. 1. Tips of the perigynia distinctly exceeding the subtending scales. 
