KEY. 209 



Flowers monoecious, convex on the back. Lower 

 pale long-awned in the fertile spikelets, awn less in the ste- 

 rile. Stamens 6. Zizania (837). 



Gr. I. 2. 



W. I. 3. 



568. I. Spikelets with 1 pale 569 



II. Spikelets with 2 pales 570 



III. Spikelets with 3 or 4 pales 598 



569. Panicle. Style short ; stigmas plumose, emerging 

 laterally from the bottom of the flower. The solitary pale 

 sometimes awned on the back. Agrostis (585). 



Gr. I. 7. 

 W. I. 4. 



Spike cylindric, with crowded spikelets. Stigmas 

 protruded at the apex of the flower. The solitary pale thin, 

 with the margins united, bag-like, awned below the middle. 



Gr. I. 3. Alopecurus. 



W. I. 10. 



570. Spikelets solitary at each joint, and each partly im- 

 bedded into a cavity of the rhachis. Glumes 2, transverse, 

 enclosing the thin pales. Stamens 3. Spikes triangular, 

 subulate, 1-3 inches long, 6-10 in number, disposed in a 

 raceme. Lepturus paniculatus, Nutt. (610). 



Gr. y. 41. 

 W. IV. 47. 



Spikelets not imbedded 571 



571. Spikes, 2 or several, placed digitately upon the 

 cuhn, or peduncle 572 



Solitary spikes, racemed spikes, or panicles 574 



579. Spikelets of 2 sorts, 2 at each joint, one sessile and 

 fertile, the other pedicelled and sterile, or abortive. Flowers 



3-paled 602 



Spikelets of one sort. Flowers 2-paled. Spikes 1- 

 sided 573 



573. Spikes 4-7 at the summit of the culm. Glumes 

 narrow, keeled ; upper pale linear, excavated by a furrow, 

 lower one laterally compressed, ovate. Stigmas 2, on an 



