POACEAE 



91 



Spikelets in panicles or racemes, usually upon 

 distinct and often long pedicels. 

 Spikelets i-flovvered. 



Empty scales 4; palets 1 -nerved. 

 Empty scales 2 (rarely 1); palet 

 usually 2-nerved. 

 Spikelets 2-many-flowered. 



Flowering scales usually shorter than 



empty ones, awn dorsal, bent. 

 Flowering scales usually longer than 

 the empty ones, awnless, or if 

 awned the awn terminal and 

 straight, rarely dorsal. 

 Spikelets borne in 2 rows: 



On one side of a continuous axis, 

 forming 1 -sided spikes or racemes. 

 On opposite sides of a continuous or 

 sometimes articulated axis, form- 

 ing equilateral spikes. 



VI. Phalarideae. 



VII. Agrostideae. 



VIII. Aveneae. 



X. Festuceae. 



IX. Chlorideae. 



XI. Hordeae. 



Represented only by 



Tribe I. Maydeae 



Tribe II. Andropogoneae 



Internodes of the rachis of the racemes thickened, appressed 

 to the pedicels of the primary spikelets, thus forming ex- 

 cavations for the reception of the secondary or sessile 

 spikelets; fertile flowering scales awnless. 

 Internodes not thickened, and without excavations for the 

 reception of the spikelets. 

 Spikelets all perfect, awned. 



Rachis of the racemes continuous; panicle axis 



short, racemes subflabellate. 

 Rachis articulated; panicle axis elongated. 

 Sessile spikelets perfect, the pedicellate staminate or 

 empty, awnless, sometimes wanting. 

 Inflorescence simple or compound, made up of I or 

 more spike-like racemes which are sessile or 

 on very short peduncles. 

 Raceme single; pedicels and internodes of the 

 rachis clavate, spongy, usually stout, with a 

 deep cup-shaped depression at the top. 

 Racemes not single; pedicels and rachis-inter- 

 nodes filiform, or flat and linear, not spongy, 

 nor appendaged at the apex. 

 Inflorescence decompound. 



Pedicellate spikelet wanting. 

 Pedicellate spikelet present. 



1. Tripsacum. 



2. Coelorachis. 



3. Miscanthus. 



4. Erianthus. 



5. Schizachyrium. 



6. Andropogon. 



7. Sorghastrum. 



8. Holcus. 



Tribe III. Zoysieae 



Represented only by 



9. Nazia. 



