4h 



PAXICEAE 



leys, where it has been introduced: mostly in the Lower Sonoran 

 Zone. 



16. ERIOCHLOA H. B. K. 



I. Eriochloa punctata (L.) Hami!. Not uncommon in fields 

 and orchards in the cutivated valleys in the southern part of the 

 State, late in the summer. Lower Sonoran Zone. 



17. VALOTA Chase. 



I. Valota saccharata (Buekl.) Chase. Common on the 

 plains and the foothills of the drier mountains throughout the State, 

 though never abundant; in the Upper Sonoran Zone. 



18. PANICUM L. 



Spikelets arranged in pairs in 1-sided racemes; 

 plant spreading by long prostrate rooting 

 stems. 



Spikelets panicled, not 1-sided; creeping stems 

 wanting. 



Leaf blades of two sorts^ those of the stem 

 broad and .short (Subgenus Dichanthe- 

 lium). 

 Spikelets over .3 mm. long; leaf blades thin; 



sheaths glabrous or sparingly hispid. 

 Spikelets not over 3 mm. long; leaf blades 

 firm: at least some of the sheaths his- 

 pid. 

 Leaf blades all alike (Panicum proper). 

 Annuals. 



Inflorescence of several more or less se- 

 cund spike-like racemes. 

 Spikelets strongly reticulate veined, 



glabrous. 

 Spikelets not reticulate veined, finely 

 pubescent and papillose-hirsute. 

 Inflorescence a more or less diffuse pan- 

 icle. 

 First glume very short, not over 1-4 the 

 length of the second; sheaths glab- 

 rous. 



First glume longer, 1-2 as long as the 

 second or longer; sheaths papillose- 

 hispid. 

 Panicle more or less drooping; culti- 

 vated plant. 

 Panicle erect; plant not cultivated. 

 Panicle large, more than half the 

 length of the entire nlant. 



1. P. aVtusum. 



P. hcUeri. 



3. /'. scribnerianum. 



P. faseiculatun 

 chartioinense. 



P. ariznnicum. 



fi. P. divhotomiflorum. 



P. iniliacewn. 



S. p. barhi))ulvinatuin. 



