GENERA OF GRASSES OF THE UNITED STATES. 165 



The species of Aristida are of distinctly minor importance for for- 

 age except in the Southwest, where several species, such as A. longi- 

 seta, are eaten by stock before the flowers are produced. The annual 

 species of the Eastern States are often found on open sterile soil, 

 and hence are called poverty grass, a name applied also to annuals of 

 other genera. 



6. NAZIEAE, THE CURLY-MESQUITE TRIBE. 



78. NAZIA Adans. 

 (Tragus Hall.) 



Spikelets 1 -flowered, in small spikes of 2 to 5, the spikes sub- 

 sessile, falling entire, the spikelets sessile on a very short zigzag rachis, 

 the first glumes small, thin, or wanting, appressed to the rachis, the 

 second glumes of the two lower spikelets strongly convex with 3 

 thick nerves bearing a row of squarrose, stout hooked prickles along 

 each side, the two second glumes forming the halves of a little bur, 

 the upper 1 to 3 spikelets reduced and sterile ; lemmas and palea thin, 

 the lemma flat, the palea strongly convex. 



Low annual grasses, with flat blades and terminal inflorescence, the 

 burs or spikes rather closely arranged along an elongate, slender axis. 

 Species three, in the tropical regions of both hemispheres ; two species 

 being introduced in the southern United States. 



Type species: Cenchrus racemosus L. 



Nazia Adans., Fam. PI. 2: 581. 1763. The genus is based on Cenchrus 

 racemosus L. 



Trains Hall., Stirp. Helv. 2: 203. 1768. Haller cites pre-Linnsean authors 

 who connect Tragus with Cenchrus racemosus L. 



Lappago Schreb., Gen. PI. 55. 1789. A new name is proposed for Tragus 

 Hall. 



Echisachys Neck., Elem. 3: 228. 1790. No species are given. The author 

 cites " Cenchrus Lin.," but his description shows that it is Linnseus's first species, 

 Cenchrus racemosus, that he is renaming. 



Nazia racemosa (L.) Kuntze, with 3 to 5 spikelets in each cluster, 

 the lower about 4 mm. long, is found in open ground from Texas to 

 Arizona, and N. aliena (Spreng.) Scribn. (fig. 96), with two spike- 

 lets in each cluster, the lower 2 to 3 mm. long, here and there through 

 the Southern States to Arizona. They are somewhat weedy grasses 

 of no economic importance. 



79. OSTEBDAMIA Neck. 



(Zoysia Willd.) 



Spikelets 1 -flowered, laterally compressed, appressed flatwise 

 against the slender rachis, glabrous, disarticulating below the glumes; 

 first glume wanting; second glume coriaceous, mucronate, or short-, 

 awned, completely infolding the thin lemma and palea, the palea 

 sometimes obsolete* 



