WOOTON AND STANDLEY FLOEA OF NEW MEXICO. 53 



Range: Western Texas and southern 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 solitary 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 1-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 ] . H. cenchroides. 



Glumes not glandular. 



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



Glumes linear or oblong, awned, the nerves approximate 3. H. jamesii. 



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 Upper 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 

 BOUtherrj New Mexico, being usually associated with black grama. Stock do not eal it 

 after it has dried, because of its bard and somewhat woody stems, Inn they thrive upon 

 it in late summer after the rains. 1 1 grows most frequently in Hats thai are sometimes 

 Hooded, being able to resist flooding for considerable periods. It is also very r< 

 ant to trampling. 



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



( i \l I KTA QBASS. 



Pleuraphis jamesii Torr. Ann. Lye. N. Y. 1: I IS. pi. It). L824. 



Tvi'K locality: "On the high plains of the Trap Formation at the Bources of the 

 Canadian Liver." Colorado or New Mexico. Type collected byJai 



K'.'.i - Wyoming and Nevada to Texa , 



New Mexico: Ahundanl on the plains from the Mogollon Mountains, Bngle, and 

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



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

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

 in the northwestern corner of the State, often forming practically pure stand 



