GRIFFITHS THE GEAMA GEASSES. 



367 



Atheropogon humilis Spreng. Syst. Veg. 1 : 293. 1825. Based upon Chondrosium 

 humile H. B. K. 



Eutriana humilis Trin. Gram. Unifl. 239. 1824. Based upon Actinochloa humilis Willd. 



Chondrosium? simplex Kunth, Rev. Gram. 1:94.1829. 

 Based upon Bouteloua simplex Lag. 



Bouteloua humilis Hieron. Bol. Acad. Cienc. (Cordoba) 

 4 : 495. 1882. Based upon Chondrosium humile Beauv. 



Bouteloua brachyathera Philippi, Anal. Mus. Nac. Chile 

 (Bot.) 8: 85. 1891. The type, no. 287 of Philippi's herba- 

 rium, has been examined. a 



Bouteloua rahmeri Philippi, Anal. Mus. Nac. Chile (Bot.) 

 8 : 85. 1891. Herb. Philippi, no. 268, Province of Terapaca, 

 Chile, is the type. It has been through my hands and 

 I find it a very good match for a specimen in the U. S. 

 National Herbarium collected by Rusby (no. 34) near 

 Yungos, Bolivia, in 1885. 



DESCRIPTION. 



A prostrate or ascending, spreading, smooth annual, 20 Fr ®' 28.-£oMfeZoua simplex. 



. „_ , . , , . , ,. , , Spikelet. Scale 7.5. From 



to 25 cm. high; culms geniculate or ascending, seldom type specimen of .B.raTmm. 



branched; sheaths smooth, deeply striate, rather loose, the 



ligule a conspicuous ring of short, white hairs; blades not abundant, short, narrow 



and inclined to be involute, about 3 cm. long; spikes terminal, normally 1 but some- 

 times 2 to 4, congested at the apex 

 of the culm, varying from 2 to 4 

 cm. long, straw colored to pur- 

 plish-tinged; spikelets commonly 

 about 50, about 8 mm. long, in- 

 cluding the awns, pectinate, con- 

 sisting of a lower perfect floret 

 and a rudiment; glumes sharply 

 and hispidulously keeled, other- 

 wise smooth, the lower about 3 

 mm., the upper 5 to 6 mm. long; 

 lemma, including awns, about 6 

 mm. long, covered on the back 

 with a long, scattered pubescence, 

 3-awned, the central awn 2 mm. 

 longer than the lateral; palet 

 smooth, obovate, awnless; rudi- 

 ment consisting of 3 hispid awns, 

 5 or 6 mm. long, together with a 

 few scales at base borne upon a 

 hairy, tufted pedicel about 1 

 mm. long; caryopsis more or less 

 triangular in vertical section, 

 about 1.5 to 1.75 mm. long, 

 slightly curved, the scutellum 



covering about two-thirds of the ventral surface. (Figures 28, 29.) 

 This description is drawn from Miguel Bang's no. 81, in the John Donnell Smith 



Herbarium, from the vicinity of La Paz, Bolivia, altitude 10,000 feet. The original 



Fig. 29 — Bouteloua simplex, a, Spikelet; b, c, lemma and 

 two views of palet of first floret; d, rudiment, a, Scale 7.5; 

 b-d, scale 15. From type specimen of B. brachyathera. 



9368°— 12- 



a See discussion, p. 368. 



