PLANTS OF SOUTHERN NEW JERSEY. 179 



//. Spikelets ovate, not flattened. 



Syntherisma, p. i88 

 ii. Flowers awned, scattered, or occupying 

 only the end of the rachis ; rachis not 

 flattened. Gymnopogon, p. 234 



hhh. Arranged on short spikes, all closely ap- 

 pressed to the main stem and scarcely over- 

 lapping. 



i. Awned. Miihlenbergia, p. 211 



ii. Not awned. 



y. Spikelets conspicuously flattened. 



Homalocenchrus, p. 215 

 jj. Spikelets ovate, not flattened. 



Paniciim, p. 189 

 hhhh. Arranged in a slender appressed panicle. 

 i. Panicle very slender, but few short 

 branches, all closely appressed, flowers 

 long awned ; awns 18-24 mm. long. 



Brachyelytrum, p. 221 

 ii. Panicle of appressed branches, flowers 

 not long awned ; awns, if present, less 

 than 10 mm. 

 j. Culms simple. 



k. Leaves involute. 



Panicum amarum, p. 196 

 kk. Leaves not involute, panicle 

 dense and feathery. 

 /. A tuft of hairs at the base 

 of the flowers within the 

 glumes. 

 Calamagrostis canadensis, p. 227 

 //. No tuft of hairs. 



fit. Inflorescence whitish or 

 reddish, erect. 



Agrostis, p. 224 

 mm. Inflorescence green 

 drooping. Cinna, p. 224 

 y/. Culms much branched with nu- 

 merous lateral panicles. 



Muhlenbergia, p. 211 

 gg. Spikelets two to many flowered. 



h. Spikes digitate or branching oflf in a fan-like 

 arrangement from the common stalk. Spike- 

 lets sessile or nearly so. 

 i. Spikelets in two definite rows, contigu- 

 ous. [Elensine indica]* 

 ii. Spikelets not in two definite rows, scat- 

 tered. Diplachne, p. 237 



* Crab grass. A common weed in lawns and about gardens. 



