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Bulletin Wisconsin Natural History Society [Vol. 11, No. 3 
tions of this may be found in the hairy varieties of many glabrous 
species; in the long, stringy branches of certain forms both of 
A. sagittifolius and A. hirsuticaulis; and in the tendency of species 
with normally close inflorescence to throw off loosely branching 
varieties with scattered heads and elongate slender pedicels. 
The causes of these variations are not easily determined. One 
class of evolutionists ascribes them all to chance; another to differ- 
ences, or changes, in environment; while another supposes that 
changes of environment have little other effect than to release the 
tension under which an unwilling genus has been held by previously 
fixed conditions, and to restore the free play of its natural exuber- 
ance. Hybridism may also play a part in stimulating variation. 
The solution of these problems will not be reached through specu- 
lation merely. Whatever the final conclusion may be, it can only* 
be arrived at when the facts of variation — the directions which it 
takes, the limitations to which it is subject and the conditions 
under which its different manifestations occur — are thoroughly 
understood. Such knowledge can only be gained through patient 
and long continued observation and through the co-operating 
labors of many observers. 
This paper is the very inadequate result of studies which were 
begun in the fall of 1902 and have occupied such leisure as could be 
devoted to them ever since that time. More or less extensive col- 
lections have been made in the eastern portion of the state, includ- 
ing Outagamie, Calumet, Sheboygan, Ozaukee, Milwaukee, Racine 
and Waukesha Counties, and much less extensive ones in Kenosha, 
Dane, Sauk, Columbia and Door Counties. These have been 
supplemented to some extent by specimens received from other 
collectors, among whom should be mentioned Dr. H. V. Ogden, 
Mr. William Finger, Mr. Howland Russel and Mr. William W. 
Wight, of Milwaukee, Prof. A. B. Stout, formerly of Wisconsin, 
now of Columbia University, Mr. H. C. Benke, of Manitowoc, 
and Mr. Samuel C. Wadmond, of Delavan. In connection with 
these studies trips have been taken and collections made in north- 
eastern Illinois, northeastern Ohio, western Massachusetts and 
northwestern Connecticut; and specimens of eastern Asters have 
been received from Mr. Carl Blomberg, of North Easton, Massa- 
chusetts, and from the Biltmore Herbarium at Biltmore, North 
Carolina. Others have been contributed by personal friends from 
