4 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
twigs, belongs decidedly to the dry, sterile uplands of the above mentioned 
c6unties. 
The composition of these forests as far as the various species of trees 
are concerned is expressed in table 2, the result of surveying typical hills 
densely covered by woods in a few counties. 
Table 2 
Name of Tree 
A Forest 
in 
Western 
Butler 
County 
% 
A Forest 
in 
Middle 
Iron 
County 
% 
A Forest 
in 
Middle 
Wayne 
County 
% 
A Forest 
in 
Southern 
Madison 
County 
% 
T^ICi m *=*f 
of 
Thickest 
Tree 
Observed 
(dm.) 
Quercus marilandica Muench 
25 
6 
15 
3 
" imhricaria yVichx 
0.3 
20 
8 
" alba L 
lO 
2 
I 
9 
" rubra L 
8 
4 
6 
8 
" macrocar pa l^i'xchx 
2.3 
10 
10 
30 
12 
" falcata Michx 
14 
15 
12 
6 
Carya glabra (Mill.) Spach 
" ovata (Mill.) Koch 
1 1 
6 
4 
12 
5 
2 
8 
6 
" alba (L.) Koch 
4 
6 
6 
Juglans nigra L 
" cinerea L 
9 
3 
6 
8 
6 
Ulmus alata Michx 
5 
2 
8 
2 
4 
4 
15 
i6 
8 
Diospyros virginiana L 
2 
15 
12 
6 
3 
Liquida?nbar Styraciflua I 
I 
8 
II 
7 
0.7 
I 
7 
Nyssa sylvatica Marsh 
some 
2 
8 
Cornus florida L 
some 
some 
2 
I 
Cercis canadensis L 
some 
some 
2 
I 
Of all these species Quercus marilandica is the most typically xerophytic 
species and especially adapted to dry barrens ; where the hills are becoming 
fertile, as toward the base of the hill near a stream, this oak species dis- 
appears completely. 
The shrub vegetation is not always heavily developed between the high 
trees, but is common toward the edge of the woods. Here are frequently 
found very extensive thickets of Symphoricarpos orbiculatus Moench 
covering several acres in extent, often forming a pure association where 
nothing else is found until the forests are entered, where the shrubs become 
gradually less abundant. Other species of shrubs and small trees which 
may grow either in pure stands or in a mixed growth are Rhus typhina L., 
R. canadensis Marsh., Ribes gracile Michx.; whole patches are covered by 
Ceanothus americanus L. and Rosa species, especially R. hlanda Ait. and R. 
pratincola Greene, whereas in other areas R. humulis Marsh, is prevalent. 
In various hills of the above described type the slopes are entirely covered by 
Vaccinium melanocarpum Mohr extending into the Quercus facies, although 
in the latter places they do not grow so densely ; they are especially common 
in the hills of the western portion of Butler County and in Wayne County; 
