490 Griccs: THE SUGAR GROVE FLORA 
satisfactory data as to their distribution and there are still 
hundreds of species the very characters of which are not yet 
understood. 
The difficulty of getting adequate data for such work at present 
may be illustrated from Fernald’s careful paper cited above, in 
which Thuja occidentalis is mapped as barely reaching Ohio whereas 
it occurs over the central and south central part of the state as 
far as Delaware, Champaign, and Highland counties; Aster macro- 
- phyllus likewise is found over northeastern Ohio to Hocking 
county, although it is given as barely touching the northeastern 
corner of the state. These illustrations are not cited in any spirit 
of criticism but at once to call attention to the importance of Jocal 
work of this sort, and to forestall criticism of the maps given 
herewith, which are probably equally faulty. 
It has seemed wise not to indicate the edges of the ranges but 
rather to show known stations. Those stations from which the 
writer has seen a specimen are marked with a “bullseye” while 
those which were compiled from the literature are marked by a 
circle without the central dot. The maps are thus capable of 
indefinite extension as more stations are found or more specimens 
seen. 
Fortunately for the purposes of this paper we have in the state 
of Ohio, thanks to the energy and enthusiasm of the late Dr. W. A. 
Kellerman, a very representative state herbarium which is indexed 
by counties after the fashion of the state maps herewith repro- 
duced. Although by no means complete as yet these maps enable 
one to learn relatively accurately the distribution of the flora over 
the state simply by glancing at the index. Curiously enough the 
distribution in Ohio often gives almost no clue as to the range 
of aspecies. Thus Populus heterophylla is confined to the northern 
half of Ohio but in Indiana it is confined to the southern portion! 
On further examination its range is found to be the Atlantic 
coastal plain from southern Connecticut around the Gulf coast 
and up the Mississippi and Wabash River systems to the basin 
of Lake Erie. 
One’s general expectation concerning plant distribution is, 
that being controlled by climate, the termini of the ranges follow 
the parallels of latitude in a general way, crossing the state from 
