GENERA OF GRASSES OF THE UNITED STATES. 99 



the opposite sides of the spike being imbricate in a row, so that the 

 spike appears to be 4-rowed. In 6-rowed barley (H. hexastichon L.) 



FIG. 49. Bottle-brush grass, Hystrix patula. Plant, X ; spikelet and floret, X 3. 



the lateral spikelets form rather distinct rows. In 2-rowed barley 

 (H. distichon L.) the lateral spikelets are all infertile and reduced, 



