318 



Bulletin No. 205 



[March, 



Figs. 89-90. — 89, P. commntaUim, 

 culm; 90, P. commutaium, spikelet 



COMMUTATA 



The species of this group are 

 rather stout, usually with smooth 

 culms. The blades are generally 

 more than 1 cm. wide, smooth, 

 and ciliate at the base. The 

 ligule is practically wanting. 

 The spikelets are finely pubes- 

 cent, from 2.5 to 3 mm. long. 



Panicum commutatum Schult. 

 (Figs. 89 and 90) 



Hitchcock and Chase '10, 303. 

 Vernal forai with culms in 

 tufts, 1 to 2.5 feet high, the culms 

 smooth ; nodes occasionally with 

 minute hairs; sheaths shorter 

 than the internodes, usually 

 smooth except for the ciliate 

 margin ; ligules not visible ; 

 blades short and broad, 2 to 7 

 inches long, 12 to 25 mm. broad, 

 smooth on both surfaces, the 

 margin ciliate at the base ; spike- 

 lets 2.6 to 2.8 mm. long, pubes- 

 cent. Autumnal form branching 

 from the middle of the culm ; 

 the leaves little reduced ; panicles 

 very small. 



This species is found mostly 

 in woods and shady places. It 

 is dull, grayish green, usually 

 tinged Avith purple. 



ILLINOIS SPECIMENS: Without lo- 

 cality, Schneck in 1879. 



LATIFOLIA 



The species belonging to this 

 group are readily distinguished 

 by their very tall culms and 

 broad, thin leaves, which are 



