466 PROCEEDINGS OF THE AMERICAN ACADEMY, 
t+ ee less than 4 mm. long. 
Per a 2 mm. or more long. 
= Pevigy nia with serrulate beaks or margin 
a. Spike elongate, from linear-cylindric to aie 
F Perigynia — broadest at base: os at or all ap- 
pro n oblong-cylindric spike (80) C. arcta. 
2. Perigynia at ne near the middle. 
O Plant glaucous : leaves 2 to 4 mm. broad: spikelets with many 
appressed-ascending glaucous obscurely beaked perigynia. 
Spikelets 6 to 10 mm. long, approximate, or the lowest 
rarely 1,5 cm. apart: perigynia 2.3 to 3 mm. long 
31) wal canescens. 
Spikelets 4 to 7 mm. long, subapproximate or remote: per 
gynia about 2mm.long (31) C. canescens, var. cnicbate 
a omnety 6 to 12 mm. oot remote, the lowest 2 to 4.cm 
apar (31) C. canescens, var. disjuncta. 
[oxe) ae sit ‘i lets ous flees to 2.5 mm. broad : Lar 
h few loosely spreading dark green or brown 
aoe cle peygvnh gc. 458)... nasil 
b. Spike subglobose, of 2 to 4 closely approximate subglobose 
loosely flowered silvery saya perigynia oblong, beakless, 
nerved, 3 to 3.4 mm. long (35) C. tenuiflora. 
= = Perigynia smooth througho ve 
a. Spike beat silvery-greer or pale brown, not ferrugineous nor 
ark brow 
1. Spike sacs at least the lower spikelets scattered. 
Uppermost spikelet divaricate-pedunculate, the lowermost 
ae ie by a ie ty leaf-like bract: perigynia ary than 
3mm. long (36) C. trisperma. 
Spikelets Biel ep in a Hocaheviliodde des spike, bract- 
less or only short-bracted : perigynia 2 to 3 mm. long 
(81) ©. canescens. 
(For vars. see above. 
2. eee subglobose, of 2 to 4 closely approximate subglobose 
sely flowered scsomea perigynia beakless, 8 mm. or more 
lon (35) C. tenuiflora. 
b. Spike recvoawicul or baits hesen 
1. Terminal spikelet with conspicuous clavate base: perigynia ab- 
ruptly beaked: culms smooth (or harsh only at tips 
O Ape aeogys the lowest 4 or5 mm. thick ; the terminal 
1 . long: splen pale, about equalled by th 
Jellowist ee blunt scales. (38) C. nor cae ' 
OO Spikelets approximate ; ba lowest i das 4 mm. thick. 
Plant weak and lax : leaves involute, 0.5 to 1.5 mm. broad : 
h ecales 
perigynia pale, equalled by tl g 
($0) C. glareosa- 
Plant stiff and upright: leaves flat, 1 to 3 mm. broad: ab 
gynia brown or reddish, —— the fuscous obtus 
ceive i oy (40) ©. iagopien 
