GRIFFITHS THE GRAMA GRASSES. 401 



forms a large part of the forage upon limited areas in the foothills in southern Arizona. 

 It is easily recognized by its woolly spikes, but may be confused with B. eludens. 



There is probably a greater difference between young and mature specimens in 

 this species than in any other of the group. If Kunth's figures are compared with . 

 the figures in this text the difference will be easily appreciated. However, my 

 specimens show conclusively that the awns and rudiment develop greatly after an the- 

 sis. It is certain that Kunth had immature plants. An examination of the specimens 

 which I am distributing under this name furnish ample proof of the position which 

 is taken here. The plant which Kunth had is also abnormally small. However, 

 this species, in exactly the form described by Kunth, has been seen in abundance 

 in closely grazed areas upon the highlands of Mexico. Upon the highlands of 

 Zacatecas, San Luis Potosi, Aguascalientes, and portions of Jalisco and Oaxaca 

 it is common to find the grass, closely grazed and trampled, forming some sem- 

 blance of a turf. Under these conditions there is a difference between this form 

 and the common forms of the more arid and stony regions which is comparable to that 

 between the B. gracilis of the prairies of the Dakotas and that of the mountains of 

 Arizona. When closely grazed and trampled the culms are short. It was a young 

 plant grown under such conditions that Kunth figured. Conzatti's no. 156 from 

 Oaxaca is a perfect match for the figures mentioned. Portions of Tourney's no. 138, 

 Pringle, "Sandy Plains near Mexican Boundary, Arizona, Aug. 8, 1884," portions of 

 Havard's no. 1, Limpio, Western Texas, July-Sept., 1883, are like the type so far as 

 some of the spikes are concerned. I consider Wilkinson 53, Pnngle 410, Lemmon 4635, 

 and 371, Griffiths & Thornber 2, Nealley 414a and 166, typical of B. havardii which is 

 the mature stage of the plant. Many of the spikes of Pringle 410 perfectly match the 

 Humboldt specimen. 



HERBARIUM SPECIMENS. 



Arizona: Hitchcock 3702, Patagonia. Griffiths 1829, Mescal; 3440, Santa Rita Forest 

 Reserve. Wilcox, Fort Huachuca. Griffiths & Thornber 2, Santa Rita Forest 

 Reserve. Lemmon, 371 "S. E. Arizona"; 4635, locality unknown. Tourney 800, 

 138, Tucson. Parish 262, Tucson. Pringle, near Mexican Boundary. 



Texas: Nealley 166, Presidio County. Havard 1, Mesquit Canyon, western Texas; 

 53, Limpio Mountains. 



Mexico: Pringle 410, Chihuahua. Wilkinson, Santa Eulalia Plains, Chihuahua. 

 Meams 1897 near Mexican Boundary Monument No. 82. Palmer 546, Durango. 

 Conzatti 156, Oaxaca. Rose 2532, Huejuquilla, Jalisco; 2782, Plateado, Zacatecas. 



22. Bouteloua eludens sp. nov. 



description. 



A tall, erect, cespitose perennial, 20 to 50 cm. high, having a general resemblance 

 in its more diminutive forms to B. chondrosioides and in some of its taller, more robust 

 forms to hairy-spiked forms of B. curtipendula; culms erect, unbranched; blades 

 rather abundant, narrow, and most radical, flat, with serrate edges, often 15 cm. long 

 and about 1 to 1.5 mm. wide; ligule reduced to a fringe of short, white hairs; inflores- 

 cence racemose, 6 to 8 cm. long; spikes 10 to 20, bilaterally arranged on a zigzag 

 axis, but so twisted on the peduncles as to appear unilateral, triangular, about 1 cm. 

 long; spikelets about 5, consisting of a lower staminate, pistillate, or perfect floret, 

 a middle staminate, pistillate, or perfect or even rudimentary floret, and an upper 

 rudiment varying from a simple prolongation of the rachilla, to a trifid-awned struc- 

 ture with two scales or to a well-developed lemma, or sometimes entirely absent; 

 glumes narrow, densely pubescent, the first acuminate, 5 to 6 mm. long, the second 

 very short-awned and about 1 mm. longer; lemma 6 to 7 mm. long, pubescent, trifid, 

 with 3 winged, short awns; lemma of second floret pubescent, about 10 mm. long, with 

 3 hairy-hispid awns, the central about 1 mm. longer than the lateral and with projec- 



