* ELISHA MITCHELL SCIENTIFIC SOCIETY. 23 
state and until one is familiar with the summer and aut- 
umnaleforms assumed by different types in the group the 
simple state is necessary in order to make a satisfactory 
determination. Habit, also, is a character of great value 
in makine determinations in this group, with specimens 
in either the simple or branched states; and habit 
should always be noted when specimens are secured. 
The leaves on the branches are much smaller than the 
primary leaves, the panicles are much smaller, and the 
spikelets are generally smaller and more acute. The 
limitations of the species are, in practically all cases, 
sharply defined and there are no intergradent forms. 
Several of the species proposed by Lamarck, Michaux, 
Muhlenburg and Elliott are yet subjects of dispute or 
even speculation, being represented by no type specimens, 
while the descriptions are not sufficiently minute for ac- 
curate determination. I have been able to examine the 
material in the Herbarium of the Philadelphia Academy 
of Natural Science, which contains many specimens of 
Nuttall, Schweinitz, Muhlenburg, and Baldwin. The 
specimens o£ Muhlenburg and Baldwin are of particular 
interest; those of Muhlenburg sometimes representing his 
own species; while Baldwin’s often indicate Elhott’s, 
since he furnished Elliott with many specimens from 
Georgia. I have, besides, been able to do considerable 
field work in the region from which Elliott derived his 
material, central and southern Georgia and eastern Caro- 
lina, and have there studied the species with the view of 
identifying some of Elliott’s species. I have found noth- 
ing so far, however, which agrees with the description of 
his Panicum ovale, P. paucifiorum or P. strigosum. 
The group of the genus that I have designated as the 
dichotomous group is best developed, so far as number of 
species is concerned, in the south Atlantic States, pro- 
bably in eastern South Carolina, or castern Georgia, 
where the number of known species will prooably amount 
