GRAMINACEAE (GRASS FAMILY) 



25 a Flat side of spikelet turned to rachis 17. Agropyrum. p 118 

 b Edge of spikelet turned to rachis 18. Lolium. p 118 



26 a i spikelet at each joint of rachis, alternate on 2 sides, 



spikelets not stalked 18. Lolium. p 118 



h Spikelets not completely as in a 27 



27 a Spikelets rather densely arranged on all sides of rachis; 



awns usually less than % in. long 



38. Anthoxanthum. p 120 

 b Spikelets loosely arranged on rachis ; awns Vi in. or more 



long 28 



28 a Spikes appear somewhat fuzzy due to a hairy stalk % 



in. or more long from each joint of the rachis 



19. Andropogon. p n8 

 b Spikes not completely as in a 29 



29 a Awns bent at right angles to spikelet; slender grasses 



20. Aristida. p 119 

 b Awns straight about i in. or more long; coarse grasses 



21. Hystrix. p //<? 



30 a Awns conspicuous, % in. or more long 31 



b No conspicuous awns % in. or more long on spikelet. . 33 



31 a Spikes appear somewhat fuzzy due to a hairy stalk 



V in. or more long from each joint of the rachis 



19. Andropogon. p 118 

 b Spikes not completely as in a 32 



32 a Awns bent at right angles to spikelet; slender grasses 



20. Aristida. p IIQ 

 b Awns straight; coarse grasses.... 22. Echinochloa. p IIQ 



33 a Spikelets not in a i-sided spike or raceme 34 



b Spikelets in a i-sided spike or raceme 36 



34 a Coarse grass usually 4 ft. or more high ; rachis easily 



breaking at the joints where sessile spikelets are at- 

 tached 16. Tripsacum. p 118 



b Grasses not completely as in a 35 



35 a Nodes of stem swollen 43. Muhlenbergia. p 120 



b Nodes of stem not swollen.... 22. Echinochloa. p 119 



36 a Spikelets rounded, flat on inner surface; leaves usually 



hairy 23. Paspalum. p IIQ 



b Spikelets more or less pointed, not flat on inner surface. 37 



37 a Spikes scattered on rachis, not clustered at top of stem 



24. Spartina. p IIQ 

 b Spikes usually conspicuously whorled or clustered .it top 



of stem 38 



38 a Spikelets 3-5-flowered; coarse grass in tufts 



25. Eleusine. p IIQ 

 b Spikelets i-flowered 39 



114 



