KEY. 211 



upon each joint of the rhachis, 2 glumes belonging to each 

 particular spikelet, and altogether forming a sort of invo- 

 lucre, only the middle spikelet fertile ; lower pale of its 

 flower long-awned from the apex. Spike dense. 



Hordeum. 



Gr. V. 44. 



W. IV. 48. 



Glumes not forming an involucre 578 



578. Apparent spike oblong-linear, ovate-oblong, or 

 cylindric — that is, a much-contracted panicle 579 



One-sided spikes racemed, sometimes 2 only. Spike- 

 lets spiked in two rows on the outer side of a triangular 

 rhachis. Glumes coriaceous, laterally compressed, keeled, 

 bristle-pointed, upper one often awned. Styles long, com- 

 monly united below. Spartina (597). 



G. 16. 



W. 60. 



579. Pales unequal, mucronate ; and the nearly equal, 

 linear glumes with their bristle-like awns twice their length. 

 Panicle spicatc, densely conglomerated, interrupted, 2-3 

 inches long. Muhlenbergia glomerata, Trin. (587). 



Lower pale with a few, minute teeth at the apex, 

 and awned ; the upper one 2 -toothed. Glumes hairy all 

 over. Contracted, spike-like panicle interrupted. 



Polypogon Monspeliensis, Desf. 



Gr. II. 8. 



W. I. 8. 



Lower pale truncate and awnless. Glumes tipped 

 with either short bristles about ^ of their length or awn-like 

 ones, as long as themselves. Spike oblong-ovate, or long, 

 cylindric. Fhleum. 



Gr. L 4. 



W. L 11. 



580. Spikelets in a loose, more or less open, or contracted 

 panicle (or raceme) 581 



Spikelets arranged in a solitary sjiike, in a spike- 

 bearing raceme, or in a spike-like, ovoid panicle 594 



581. Lower pale awned 582 



Lower pale awnless 588 



