MANUAL OF THE GRASSES OF THE UNITED STATES 



cm. long; culms erect, slender, 10 to 

 30 cm. tall, villous at the nodes; 

 blades flat, 1 to 2 mm. wide, scabrous, 

 more or less pilose, usually short, 

 crowded at base, often forming a 

 curly tuft, but sometimes longer and 

 erect; spike usually 2 to 3 cm. long, 

 with mostly 4 to 8 clusters of spike- 

 lets, the axis flat, the internodes 

 alternately curved, 3 to 5 mm. long; 

 group of spikelets 5 to 6 mm. long; 

 lateral spikelets attenuate at base, 

 the glumes united below, firm, sca- 

 brous, the outer lobe broadened up- 

 ward, 2- to 3-nerved, the inner much 

 reduced, the midnerve of both glumes 

 extending into short awns, the first 

 glume smaller, the lateral nerves 

 sometimes excurrent into awns or 

 teeth (the glumes variable in a single 

 spike) ; fertile spikelet usually shorter 

 than the sterile, rounded at base; 

 glumes firm with deeply lobed thinner 

 upper part, the midnerves extending 

 into awns mostly exceeding the 

 staminate spikelets; lemma com- 

 pressed, narrowed above, awnless 91 

 ( H. texana Nash. ) — Mesas and plains, 

 Texas to Arizona and northern Mex- 

 ico. H. cenchroides H. B. K., to 

 which this species has commonly been 

 referred, is confined to Mexico. H. 



BELANGEEI Var. LONGIFOLIA (Vasey) 



Hitchc. Stolons wanting; blades elon- 

 gate. % — Arizona and Sonora. 



2. Hilaria swalleni Cory. (Fig. 716.) 

 Resembling H. belangeri, culms to 

 35 cm. tall; blades usually 2 mm. 

 wide, scarcely curled; spike 2 to 4.5 

 cm. long, with 3 to 8 clusters of 

 spikelets, the internodes of the flat 

 axis 4 to 6 mm. long; glumes of 

 lateral spikelets similar, oblong, nar- 

 rowed at base, about equaling the 

 florets, firm and strongly pigmented 

 except toward the summit, the nerves 

 often rather obscure; awns of all 

 glumes slightly longer than those of 

 the preceding; fertile spikelet about 

 equaling the sterile, the fertile floret 

 slightly larger than in H. belangeri. 

 % — Mesas and rocky plains, west- 

 ern Texas and northern Mexico. Said 

 to be better forage than H. belangeri. 



487 



Figure 716. — Hilaria swalleni. Two views of group of 

 spikelets, X 5. (Young 46, Tex.) 



Figure 717. — Hilaria mutica, X 1. (Tourney, Ariz.) 



3. Hilaria mutica (Buckl.) Benth. 

 Tobosa grass. (Fig. 717.) Culms 

 from a tough rhizomatous base, 30 



