MANUAL OF THE GRASSES OF THE UNITED STATES 



489 



to 60 cm. tall, glabrous, the nodes 

 pubescent; blades flat or somewhat 

 involute, rather rigid, 2 to 3 mm. 

 wide; spikes 4 to 6 cm. long; group of 

 spikelets about 7 mm. long; bearded 

 at base; glumes of lateral spikelets 

 very unsymmetrical, widened toward 

 the ciliate summit, the nerves fla- 

 bellate, not excurrent or barely so; 

 fertile spikelet about equaling the 

 lateral ones, its glumes strongly 

 keeled, cleft into few to several nar- 

 row ciliate lobes and slender awns; 

 lemma exceeding the glumes, mucro- 

 nate between 2 rounded lobes. % 

 (Plearaphis mutica Buckl.) — Dry 

 plains and hills, Texas to Arizona 

 and northern Mexico. 



4. Hilaria jamesii (Torr.) Benth. 

 Galleta. (Fig. 718.) Plants erect, 

 the base often decumbent or rhi- 

 zomatous, bearing also tough scaly 

 rhizomes; culms glabrous, the nodes 

 villous; sheaths glabrous or slightly 

 scabrous, sparingly villous around the 

 short membranaceous ligule; blades 

 mostly 2 to 5 cm. long, 2 to 4 mm. 

 wide, rigid, soon involute, the upper 

 reduced; group of spikelets 6 to 8. mm. 

 long, long-villous at base, similar to 

 those of H. rigida, but the glumes of 

 lateral spikelets acute, usually with 

 a single awn; lemma of the fertile 

 spikelet exceeding its glumes. % 

 (Pleuraphis jamesii Torr.) — Deserts, 

 canyons, and dry plains, Wyoming 

 and Utah to Texas and Inyo County, 

 Calif. 



5. Hilaria rigida (Thurb.) Benth. 

 ex Scribn. Big galleta. (Fig. 719.) 

 Plants rather robust at base, branch- 

 ing, the branches mostly erect or as- 

 cending, the base rather woody, de- 

 cumbent or rhizomatous; culms nu- 

 merous, rigid, felty-pubescent, gla- 

 brate and scabrous above, 50 to 100 

 cm. tall; leaves felty or glabrous, 

 usually woolly at the top of the 

 sheath; blades spreading, 2 to 5 cm. 

 long, or longer on sterile shoots, 2 

 to 4 mm. wide, more or less involute, 

 acuminate into a rigid coriaceous 

 point; group of spikelets about 8 mm. 

 long, densely bearded at base; glumes 



of lateral spikelets thin, long-ciliate, 

 about 7-nerved, usually 2- to 4-lobed 

 at the broad summit and with 1 to 

 3 nerves excurrent into slender awns, 

 nerves sometimes obscure and scarce- 

 ly excurrent (variable in a single 

 spike) ; fertile spikelet about equaling 

 the lateral ones, its narrow glumes 

 deeply cleft into few to several acumi- 

 nate ciliate lobes and slender awns; 

 lemma scarcely exceeding the glumes, 

 thin, ciliate, 2-lobed, the midnerve 

 excurrent into a short awn. % 

 (Pleuraphis rigida Thurb.) — Deserts, 

 southern Utah and Nevada to Ari- 

 zona, southern California, and Sonora. 



Figure 719. — Hilaria rigida, X 1. (Palmer 494, 

 Utah.) 



96. AEGOPOGON Humb. and Bonpl. 

 ex Willd. 



Spikelets on short flat pedicels, in 

 groups of 3, the group short-pedun- 

 culate, spreading, the peduncle dis- 

 articulating from the axis and form- 

 ing a pointed stipe below the group, 

 this falling entire; central spikelet 

 shorter pedicellate, fertile, the two 

 lateral ones longer pedicellate and 

 staminate or neuter; glumes mem- 

 branaceous, notched at the apex, the 



