GENERA OF GRASSES OF THE UNITED STATES. 167 
80. Hilaria H. B. K. 
Spikelets sessile, in groups of 3, the groups falling from the 
axis entire, the central spikelet (next the axis) fertile, 1 -flowered, the 
2 lateral spikelets staminate, 2-flowered ; glumes coriaceous, those of 
the 3 spikelets forming a false involucre, in some species connate 
at the base, more or less asymmetric, usually bearing an awn on 
Fig. 97. — Manila grass, Osterdamia matrella. Plant, X 1 ; spikelet, X 10 ; floret with 
caryopsis, the palea obsolete, X 10. 
one side from about the middle; lemma and palea hyaline, about 
equal in length. 
Perennial low grasses, the groups of spikelets appressed to the 
axis, in terminal spikes. Species five, in arid regions, southwestern 
United States to Central America, all but one found within the limits 
of the United States. 
Type species: Hilaria cenchroides H. B. K. 
Hilaria H. B. K., Nov. Gen. and Sp. 1 : 116. 1816. Only one species described. 
