DESCRIPTIONS OF TRIBES AND GENERA. 65 



III. Two outer spikelets $ , two-flowered ; one 

 inner $ , one-flowered. . . . 39. Hilaria. 

 B. Spikelets solitary, very rarely two upon each internod,e of 

 the rachis. 



a. Empty glumes three, the third often having the 

 function of the flowering glume of a $ flower. 



44. Neurachne. 



b. Empty glumes two, these much longer than the 

 flowering glume. 



a. Both empty glumes with hooked spines upon- 



the back, awnless 42. Latipes. 



/?. Both empty glumes with a fringed crest upon 



the back, awnless 43. Lopholepis. 



y. Both empty glumes smooth. 



I. Empty glumes with long awns. 45. Perotis. 

 II. Empty glumes subulate, awnless. 



46. Leptothrium. 



c. Empty glume one. 



a. Empty glume coriaceous, acute, awnless. 



47. Zoysia. 

 ft. Empty glume with 3-5 awns. . 48. Schaffnera. 



37. (64) Trachys Pers. (Trachyozus Keichb., Trachys- 

 tachys Dietr.). The outer spikelets of the clusters $ , 

 the inner 1-3 ; the third glume very large, coriaceous, 

 all the others much smaller. 



Species one ( T. mucronata Pers.), on the sea shores of 

 western India. 



38. (63) Anthephora Schreb. (Fig. 21). Eachis strongly 

 flexuose, spikelets fitting exactly into the curves in the 

 joints. Pseudo-involucre below with 3-5 deep incisions ; 

 all spikelets , awnless. 



Species five ; one in tropical America, the others in 

 tropical and southern Africa. 



39. (60) Hilaria Kunth (Hexarrhena Presl, Pleuraphis 

 Torr.). Empty glumes of the spikelets two-cleft, with 

 one to several awns, those of the $ spikelets very obtuse, 

 short awned or awnless. Flowering glume awnless or 

 mucronate-pointed. 



Species five, from Central America to California and 

 Texas. 



