MANUAL OF THE GRASSES OF THE UNITED STATES 499 



Several species are found on the plains of Texas, where they form 

 part of the forage for grazing animals. C. virgata is a rather common 

 annual weed in the Southwest especially in alfalfa fields. It may be 

 locally abundant and then furnishes considerable forage. C. gay ana, 

 Rhodes grass, is cultivated in the irrigated regions of the Southwest, 

 where it is valuable as a meadow grass. It is also used in the Hawaiian 

 Islands on some ranches in the drier regions. 



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Figure 1059.— Gymnopogon chapmanianus. Plant, X 1; florets, X 5. (Tracy 7102, Fla.) 



Lemmas firm, dark brown, awnless or mucronate. Perennials with strongly 

 compressed culms and sheaths, and firm flat or folded blades abruptly 

 rounded at the tip Section 1. Eustachys. 



Lemmas distinctly awned, (awn very short in C. cucullata) , pale or fuscous. 



Section 2. Euchloris. 



Section 1. Eustachys 



Spikes numerous, usually more than 10 1. C. glaeca. 



Spikes usually not more than 6. 



Spikelets 2 mm long; lemmas dark 2. C. petraea. 



Spikelets 3 mm long; lemmas pale to golden brown until maturity. 



Spikes 2, sometimes 1 or 3 3. C. florid ana. 



Spikes 4 to 6 4. C. neglecta. 



Section 2. Euchloris 



Rudiment narrow, oblong, acute, often inconspicuous. (Second rudiment 

 truncate in C. gayana!) 



Plant producing long, stout stolons 5. C. gayana. 



Plant not stoloniferous (occasionally with short stolons in C. andropogonoides) . 

 Fertile lemma about 2.5 mm long; plants mostly less than 50 cm tall; spikes 



mostly less than 10 cm long 7. C. andropogonoides. 



Fertile lemma 4 to 7 mm long; plants 40 to 100 cm or more tall; spikes 

 mostly more than 10 cm long. 

 Blades folded, abruptly acute or rounded; spikes whorled, naked at base. 



8. C. TEXENSIS. 



Blades flat, long-acuminate; spikes racemose on a short axis, solitary or 



in small fascicles 6. C. chloridea. 



Rudiment truncate-broadened at apex, usually conspicuous (rather narrow in 

 C. virgata). 

 Lemma conspicuously ciliate-villous, the spikes feathery. 



Plants annual. Lemma long-ciliate on the lateral nerves near apex. 



9. C. Virgata. 

 Plants perennial. 



Spikes flexuous, nodding, mostly 10 to 15 cm long; hairs much exceeding 



the spikelets 10. C. polydactyla^. 



Spikes straight or subflexuous, 5 to 7 cm long; hairs about equaline; the 

 spikelets _ 11. C. ciliata. 



