88 UNIVERSITY OF MISSOURI STUDIES [^30 



53. P. implicatum Scribn. 



Dry thickets and hills; common: well marked by its pap- 

 illose-hirsute sheaths and leaves, but varying into the various 

 species of this difficult group, 



Maine to Missouri. 



54. P. dichotomum L. 



Woodlands, thickets, wild fields and pastures, chiefly in 

 dry soil: exceedingly variable. 

 Connecticut to Texas. 



54 a. P. dichotomum fasciculatum Wats. 



The common form in pastures and fields, the fasciculate 

 autumn condition of which is well known. 



Range of the type. 



54 b. P. dichotomum commune Wats. 



The form usual in open thickets, and when growing in 

 fields with rich soil. 

 Range of the type. 



54 c. P. dichotomum gracile Wats. 



The strictly sylvan form with slender culms and long pe- 

 dunculate panicles. 



Range of the type. 



54 d. P. dichotomum villosum Vasey. 



Dry hills: often quite distinct, but sometimes verging into 

 the other pubescent species of the group. 



Range of the type. 



55. P. nitidum Lam. 



Dry thickets: a pilose form. 



Massachusetts to Michigan; Georgia to Missouri. 



56. P. lanuginosum Ell. 



Dry thickets and the bluffs of streams. 

 New Jersey and Florida to Missouri. 



57. P. commutatum Schultes. 



Wild dry hills, especially in thickets: a form on Pansy 

 Hill and on red clay barrens is very short, with narrower 

 leaves and smaller panicles, appearing often quite distinct, 



