FLOWERING PLANTS AND FERNS OF ARIZONA 135 



where in favorable seasons it is cut for hay. Rhodesgrass (C gayana) 

 is grown to a very limited extent in the irrigated districts of southern 

 Arizona as a pasture and hay crop. 



Key to the species 



1. Plants annual; margins of the lemma short-ciliate on the lower part, long-ciliate 



on the upper third, the hairs as much as 4 mm. long _ 1. C. virgata. 



1. Plants perennial; margins of the lemma rather evenly ciliate or, if longer, 



ciliate above, then the hairs much less than 4 mm. long (2). 



2. Plants coarse, sparingly stoloniferous; rudiment composed of 2 sterile florets, 



the lower nearly as long as the fertile one, the upper floret very much 



reduced; spikes ascending 2. C. gayana. 



2. Plants slender, tufted, not stoloniferous; rudiment composed of 1 reduced 

 floret; spikes widely spreading 3. C. latlsquamea 



1. Chloris virgata Swartz, Fl. Ind. Occ. 1: 203. 1797. 



Chloris elegans H. B. K., Nov. Gen. et Sp. 1: 166. 1816. 



Mohave, Pinal, Cochise, Santa Cruz, and Pima Counties, a common 

 weed in open ground and waste places. Nebraska to Texas, west to 

 Nevada, Arizona, and southern California, introduced in a few eastern 

 localities; tropical America. 



2. Chloris gayana Kunth, Rev. Gram. 1: 89. 1829. 



Pinal and Pima Counties, escaped from cultivation near Sacaton 

 and Tucson. North Carolina and Florida, west to southern Cali- 

 fornia; tropical America; introduced from Africa. 



3. Chloris latisquamea Nash, Torrey Bot. Club Bui. 25: 439. 1898. 

 Santa Cruz River at La Noria, Santa Cruz County (Mearns 1205). 



Texas, Arizona, and northeastern Mexico. 



55. TRICHLORIS 



Tufted, leafy perennial with several narrowly ascending spikes 

 crowded on a short axis; spikelets 2-flowered, the upper one reduced; 

 glumes acuminate, 1-nerved, persistent; lemmas rounded on the back, 

 obscurely 3-nerved, 3-awned; palea broad, slightly exceeding the 

 lemma. 



1. Trichloris mendocina (Phil.) Kurtz, Univ. Cordoba Facult. Cienc. 

 Exact. Mem. 1896: 37. 1897. 



Chloris mendocina Phil., An. Univ. Chile 36: 208. 1870. 

 Trichloris fasciculata Fourn., Mex. PL 2: 142. 1886. 



Pinal, Maricopa, Cochise, and Pima Counties, up to 4,000 feet, 

 mesas and rocky hills. Texas to Arizona and northern Mexico; 

 southern South America. 



A rather large showy grass, rarely cultivated as an ornamental. 



56. BOUTELOUA. Grama 



Cespitose or sometimes stoloniferous annuals or perennials with 

 slender culms and one to many short 1 -sided spikes, these racemose* on 

 a short or often elongate axis; spikelets with 1 fertile floret, and 1 or 



2 rudimentary florets above it; fertile lemma 3-nerved, variously 

 lobed or dentate at apex, the nerves usually excurrenf in short awns; 

 rudiment reduced to 3 awns, glumaceous and lobed, or dentate with 



3 usually conspicuous awns. 



