104 ME. a. BENTHAM OK GKAMINEJi!. 



flexuose rhachis of the spikes bordered by a narrow merabraue, 

 in the flowering glume and palea vey small and thin, ressmbling 

 lodicules, and a few other minor points. It is being figured for 

 the forthcoming part of Hooker's loones. 



13. BouTELOUA, Lag. (EiUriana, Tela., Actlnochloa, Willd.), 

 comprises about twenty-five American species, northern or 

 southern, but chiefly western. As ia the four preceding genera, 

 the spikes are distant along the main peduncle, and often nume- 

 rous, very rarely reduced to one or two ; but they are usually 

 short, with the spikelets densely crowded in two rows on one side 

 of the rhachis, and the rhachiUa always continued beyond the 

 single hermaphrodite flower, bearing one to three empty glumes 

 or awns, or sometimes a male flower. The flowering and upper 

 empty glumes usually end in three or five lobes, points, or awns ; 

 but they are often exceedingly variable in this respect even in 

 the same specimen, and it becomes difiicult to make much use 

 of them in the arrangement of the species. The following four 

 sections, raised by some to the rank of genera, are founded chiefly 

 on inflorescence :—(l) Ghondrosia or Ghondrosium, Desv. Spikes 

 usually few, often rather long, with numerous spikelets (more 

 than twelve) neatly pectinate, and the terminal empty glume 

 usually three-awned ; the species rather numerous, especially in 

 Mexico, where they run much one into another. (2) Atheropo- 

 gon, Muehl., including JSeterostega or Seterosteca, Desv. Spikes 

 often numerous, but usually very short with few (rarely above 

 twelve) spikelets, crowded but scarcely pectinate, or almost re- 

 duced to clusters, the terminal empty glume varying from three- 

 awned to entire, or reduced to a single bristle. The species best 

 known, B. racemosa, Lag. {Atlieropogon apludoides, Muehl., 

 Dinebra curtipendula, DC), was associated by DeCandolle and 

 Beauvois with the Dinehra arahica of Jacquin, which, however, 

 diflfers essentially in il;s several-flowered spikelets. (3) Tria- 

 thera, Desv. Spikes still further reduced than in Atheropogon, 

 consisting usually of two to four spikelets so narrow and so close 

 together as to appear like a single one, and perhaps sometimes 

 really only a single one, the upper empty glume reduced to three 

 awns, as in several species of the preceding section. There appear 

 to be two species, B. arktidoides {Dinehra aristidoides, H. B. K., 

 forming the genus Aristidium, Eudl.), with two to four spikelets 

 to each spike, and B. triathera, to which I should, with Munro, 

 refer both Triathera, Desv., and Tricena, H. B. K. The spike- 



