WOOTON AND STANDLEY FLORA OF NEW MEXICO. 53 



Range: Western Texas and Bouthern Arizona to Mexico, and throughout tropical 

 America. 



New Mexico: Mogollon Mountains; Mangas Springs; Lake Valley; Socorro; Dem- 

 ing; Burro Mountains; Organ Mountains; Carrizozo. Dry sandy soil, in the Lower 

 Sonoran Zone. 



11. HILARIA H. B. K. 



Cespitose or decumbent perennials, often stoloniferous, with flat or involute leaves 

 and terminal soUtary spikes; spikelets sessile, in groups of 3 at each joint of the flexu- 

 ous continuous rachis, the groups falling off entire, the 2 outer or anterior spikelets 

 staminate and 2 or 3-flowered, the posterior or inner one pistillate or hermaphrodite 

 and l-flowered; glumes firm, unequal, many-nerved, more or less connate below, 

 entire at the apex or divided, usually unequally 2-lobed with 1 to several inter- 

 mediate awns or awnlike divisions; lemmas narrow; stamens 3; styles united below; 

 grain ovoid or oblong, free. 



KEY TO THE SPECIES. 



Base of glumes with black or purplish glands 1. H. cenchroides. 



Glumes not glandular. 



Glumes cuneate, awnless, the nerves divergent 2. 77. mutica. 



Glumes linear or oblong, awned, the nerves approximate 3. //. jamcsii. 



1. Hilaria cenchroides H. B. K. Nov. Gen. & Sp. 1: 117. pi. 37. 1816. 



Texas curly mesquite grass. 



Type locality: "Crescit in planitie montana regni Mexicani, inter Zelaya et 

 Guanaxuato, locis subfrigidis, alt. 980 hexap." 



Range: Western Texas and southwestern New Mexico and southward. 



New Mexico: Mangas Springs; Cook Spring. Dry hills, in the LTpper Sonoran 

 Zone. 



2. Hilaria mutica (Buckl.) Benth. Journ. Linn. Soc. Bot. 19: 62. 1881. 



Tobosa grass. 



Pleuraphis mutica Buckl. Proc. Acad. Phila. 1862: 95. 1863. 



Type locality: "Northern Texas." 



Range: Western Texas to southern Arizona and adjacent Mexico. 



New Mexico: Common on the plains and low hills from the Black Range and 

 White Mountains southward; also collected by Bigelow at Laguna Colorado. Lower 

 and Upper Sonoran zones. 



Tobosa grass is one of the most important range grasses on the plains and mesas of 

 southern New Mexico, being usually associated with black gxama. Stock do not eat it 

 after it has dried, because of its hard and somewhat woody stems, but they thrive upon 

 it in late summer after the rains. It grows most frequently in flats that are sometimes 

 flooded, being able to resist flooding for considerable periods. It is also very resist- 

 ant to trampling. • 



3. Hilaria jamesii (Torr.) Benth. Journ. Linn. Soc. Bot. 19: 62. 1881. 



Galleta grass. 



Pleuraphis jamesii Ton . Ann. Lye. N. Y. 1: 148. pi. 10. 1824. 



Type locality: "On the high plains of the Trap Formation at the soiirces of the 

 Canadian River," Colorado or New Mexico. Type collected by James. 



Range : Wyoming and Nevada to Texas. 



New Mexico: Abundant on the plains from the Mogollon Mountains, Engle, and 

 the White Mountains northward and eastward. Plains, in the Upper Sonoran Zone. 



Galleta grass occupies the same position in northern New Mexico as tobosa in the 

 southern part. It is by far the most abundant and characteristic plant on the piains 

 in the northwestern comer of the State, often forming practically pui'e stands for 



