GRIFFITHS THE GRAMA GRASSES. 



389 



by old growth, at its base, trie leaves are more lax, ascending, and longer, and the 

 culms are more leafy above. 



Specimens are abundant in American herbaria. They are usually referred to B. 

 burkii and B. trifida in about equal numbers. The range of the species is from the 

 Rio Grande region of Texas southward to San Luis Potosi and westward to Tucson, 

 Arizona. 



HERBARIUM SPECIMENS. 



The following are typical of B. burkii: 

 Texas: Reverchon 162, Coleman and Tom Green Counties; 1361J and 1361,« Llano; 



1408, Sabinal Canyon; 3440, Upper Concho, in Curtiss N. Amer. Plants. Jermy, 



Bexar County. Smith 97, San Diego. Tracy 8230, Colorado; 8896, Kingsville. 



Nealley, Cotula, 1888. Piper, Kingsville, 1906. Letterman, Laredo, July, 1882. 



Berlandier 1427. 

 Mexico: Pringle 1974 and 11735, Monterey; Palmer 370, Victoria. 



The following herbarium specimens are typical of B. trifida (Pl. 74, A.): 

 Arizona: Pringle, mesas near Tucson, 1884. Griffiths 2448, Tucson. 

 New Mexico: Wright 2022 of 1851-52. 



Texas: Vasey, El Paso, 1881. Reverchon & 1408 (Texas Plants), Sabinal Canyon. 

 Mexico: Palmer 522 and 402, Saltillo. 



The following specimens appear to stand mid- 

 way between the two forms in some characters, 

 usually due to long awns combined with softness 

 and laxity of leafage: 

 Arizona: Lemmon, Hackberry 1889. 

 Texas: Canly 270, Spofford Junction. Reverchon 



37; 361, Llano (Texas Plants); 1408, Sabinal 



Canyon. Jermy 212, Bexar County. Plank, 



El Paso, 1894; 1, Llano. Eavard 30, mouth of 



Pecos. Mearns 1215, Fort Clark. 

 Mexico: Pringle 412, Chihuahua. Palmer 552, Vic- 

 toria; 1355, Monclova. Parry & Palmer 945, 



San Luis Potosi. Wilkinson, Santa Eulalia 



Plains, Chihuahua, 1885. Mearns 1201, La 



Noria, Sonora. 



14. Bouteloua sonorae sp. nov. 



description. 



Fig. 43. — Bouteloua sonorae. a, Spike- 

 let; b, c, lemma and palet of first 

 floret; (Z,e, rudimentary lemma and 

 palet of second floret; f, rudiment of 

 third floret; g, h, two views of cary- 

 opsis. a, Scale 7.5; b-h, scale 10. 

 From type specimen. 



A low, spreading, or half-erect perennial, 12 to 15 

 cm. high; culms simple, stoloniferous or simply 

 geniculate; sheaths close, striate, smooth, the ligule 

 a rather long fringe of white hairs; blades mostly radical, narrow, short, acuminate, 5 to 

 10 cm. long, decreasing upward to often 1 cm. long, revolute; panicle racemose, about 

 4 cm. long; spikes 2 to 4, mostly 4, about 12 to 14 mm. long, recurved at the apex; spike- 

 lets about 30, pectinate, about 2.5 mm. long, consisting of a lower perfect floret and an 

 upper rudiment; glumes smooth except for a few long white hairs on the keel, not 

 awned, the second 1.5 mm. long, the first a little shorter; lemma hairy, 3-nerved, shortly 

 3-awned, 2.3 to 2.5 mm. long, including awns; palet concave, shortly 2-awned, a trifle 

 shorter than its lemma; rudiment of 3 awns interspersed with short, blunt scales 

 upon a short, hairy-tufted stipe, about 0.5 mm. long; caryopsis not seen. (Figure 43.) 



a Typical B. burkii and B. trifida are on the same sheet of no. 1361, Texas Plants. 

 b Three sheets of this are placed in as many groups. 



