GRIFFITHS THE GRAMA GRASSES. 365 



without description in an earlier a paper. See also U. S. Dept. Agr. Div. Bot. Bull. 

 12 1 : pi. 42. 1890. 



Chondrosium tenue Willd.; Beauv. Ess. Agrost. 158. 1812. Beauvois publishes 

 "Actinochloa tenuis Willd. mss. " on page 41 and makes the above combination in his 

 index on page 158. He, however, gives no description. In his private copy of the 

 above-cited work he has written "'= Bouteloua simplex Lag. and Actinochloa, Roe- 

 iner." See also H. B. K. Nov. Gen. & Sp. 1 : 176. pi. 57. 1816. Plainly distin- 

 guishable by the figure and description. 



Actinochloa procumbens Roem. & Schult. Syst. Veg. 2 : 417. 1817. Based upon 

 Chloris procumbens. 



Actinochloa tenuis Willd.; Roem. & Schult. Syst. Veg. 2 : 418. 1817. Chondrosium 

 tenue H. B. K. is cited as a synonym. 



Actinochloa prostrata Roem. & Schult. Syst. Veg. 2 : 419. 1817. Based upon Boute- 

 loua prostrata. 



Eutriana tenuis Trin. Gram. Unifl. 240. 1824. Based upon Actinochloa tenuis Willd. 



Chloris filiformis Port'.; Kunth, Rev. Gram. 1 : 93. 1829. Mentioned as a synonym 

 of Chondrosium tenue. 



Chloris tenuis Poir.; Kunth, Rev. Gram. 1 : 93. 1829. A herbarium name cited as 

 synonym of Chondrosium tenue. 



Chondrosium? prostratum Kunth, Rev. Gram. 1 : 94. 1829. Based upon Bouteloua 

 prostrata Lag. See also Sweet. Hort. Brit. 1 : 455. 1826; Fourn. Mex. PI. 2 : 138. 1881. 



Bouteloua tenuis Griseb. Abh. Ges. Wiss. Gottingen 19 : 211. 1874. (Plantae 

 Lorentzianae.) Based upon Chondrosium tenue. 



Bouteloua pusillaY&sey, Bull. Torrey Club 11:6. 1884. The type, in the National 

 Herbarium, was collected by Vasey at Kingman, New Mexico, June, 1881. 



DESCRIPTION. 



A small, smooth, cespitose, prostrate or ascending, sparingly branched, annual, 

 attaining its best development above an altitude of 1,600 meters; sheaths smooth, 

 striate, with reduced, shortly pubescent ligules and few narrow blades only 2 to 3 cm. 

 long; spikes solitary, 1.5 to 2 cm. long, revolute toward maturity, fertile to the end of 

 the rachis; spikelets consisting of one lower fertile floret and an upper rudiment; glumes 

 keeled, acuminate, pointed but awnless, the first smooth, about 3 mm. long, the second 

 minutely hispid on the keel and 4 to 5 mm. long; lemma broadly oval, with 3 hispid, 

 unequal awns, the central the longest and expanded with wing-like projections below; 

 palet broadly obovate, smooth, broadly rounded above, about 3 mm. long, rudiment 

 consisting of 3 equal, hispid awns, about 4 mm. long, together with 2 or 3 very small 

 scales upon a naked stipe bearing a tuft of white hairs at its apex; caryopsis about 2 

 mm. long, 0.75 mm. wide, obovate, the scutellum covering tbe entire ventral and 

 curving back over a portion of the dorsal surface. (Figure 27.) 



When thinly distributed, especially upon loose fertile soils, this species forms large 

 bunches which are more likely to be prostrate than when the plants are crowded and 

 smaller. 



As a forage plant it is of very little value on account of its diminutive size and the 

 ease with which it pulls up when grazed. Indeed^ it has never been met with in 

 sufficient abundance to be much of a factor in feed production. 



Specimens representing my conception of the species are Pringle 6450, 11218, 

 Palmer 176, 332, 503, 712, Metcalfe 583. Pringle 1434, Chihuahua, and 6450, Federal 

 District of Mexico, and Schaffner 156, San Luis Potosi, approach the heavy-spiked 



a Var. Ciena 2 4 : 141. 1805. 



