Key to Tribes 



A. Spikelets laterally compressed with midrib or keel as an axis; spikelets with 

 1-several fertile florets 

 B. Spikelets unisexual, lower branches of inflorescence' staminate; glumes 



absent ZIZANIEAE (Zizania aquatica) 



B. Spikelets perfect; glumes present or absent 



C. Spikelets strongly flattened, containing 1 floret 



ORYZEAE (Leersia) 



C. Spikelets not strongly compressed, florets 1-several 



D. Spikelets in 2 rows along one side of the rachis, forming 



1-sided spikes CHLORIDEAE 



D. Spikelets not forming 1-sided spikes (Nardus of Triticeae 

 appearing 1-sided, lacks glumes) 

 E. Spikelets sessile, 2-ranked from opposite sides of the 



rachis, forming simple spikes TRITICEAE (HORDEAE) 



E. Spikelets pedicelled, not forming simple spikes (some 

 species with spike-like inflorescences but spikelets not 

 sessile) 

 F. Glumes shorter than the lowest floret 



POEAE (FESTUCEAE) 



F. Glumes (at least 1) longer than the lowest floret 



G. Spikelets containing 2 or more perfect florets 

 (staminate or sterile florets, if present, above the 



perfect) AVENEAE 



G. Spikelets containing 1 perfect floret (staminate 

 or sterile florets below it) 



H. Spikelets lacking staminate or sterile florets 



below the perfect floret .... AGROSTIDEAE 



H. Spikelets with staminate or sterile florets 



below the perfect floret PHALARIDEAE 



A. Spikelets dorsally compressed with keel or midrib in middle of flattened 

 side; spikelets with 1 fertile floret 

 I. Spikelets of unisexual florets, staminate or pistillate, not both (pistillate 



flowers in "ears") TRIPSACEAE (Zea mays) 



I. Spikelets of perfect florets or perfect and staminate, but lacking 

 pistillate florets 



K. Spikelets paired at each joint of the rachis, of 2 kinds, one sessile 

 with a perfect floret, the other a hairy pedicel with or without a 

 staminate floret (rarely with 2 stalked florets) 



ANDROPOGONEAE 



K. Spikelets mostly 1 at each joint of the rachis, all alike, florets 

 perfect 



L. Spikelets with perfect floret below and a sterile lemma 

 resembling the second glume above; glumes falling off with 



mature fruiting spikelets PANICEAE 



L. Spikelets with 1 perfect floret, lacking a sterile lemma; glumes 

 persistant after mature spikelets fall off 

 AGROSTIDEAE (Milimn) 



