1922] McDOUGALL—SYMBIOSIS 207 
probably are of relatively little importance from the viewpoint of 
symbiosis or other ecological relations. This is obviously even 
more true of the algae in such a habitat as this. The microfungi, 
however, will have to be considered in some detail later in a dis- 
cussion of their symbiotic relations with other plants. Aside from 
these three groups, the lists of species are believed to be fairly 
complete, except that there are probably a few late fall-blooming 
plants, mostly composites, that have been missed owing to the fact 
that the last survey of the season was interfered with by duties in 
connection with the opening of the University and the beginning 
of classwork for the year. 
The lists of species which have been compiled include : 31 trees, 
12 shrubs, 6 lianas, 134 herbs, 5 ferns, and 83 higher fungi. These 
figures show that while there is by no means a paucity of species, 
yet for a sixty acre deciduous forest the flora cannot be said to be 
an especially rich one. It is not unlikely that the years preceding 
the acquirement of this property by the University, when it was 
frequently pastured and the public was allowed to dig up plants 
by the roots and carry them away at will, had their effect in redu- 
cing the number of species. 
Acer saccharum and Ulmus americana are the dominant trees. 
These two are present in nearly equal numbers, the count showing 
1987 maple and 2073 elm individuals. No other species are nearly 
so abundant as these two. The nearest competitor is Fraxinus 
americana with 537 individuals, then follow F. guadrangulata with 
336, Tilia americana with 321, and Carpinus caroliniana with 303 
representatives. All other species are represented by less than 300 
individuals. These data show at once that the forest is typically 
hydrarch mesophytic and relatively mature, Acer saccharum being 
the most typical climax species of the region. While these species 
are all found more or less throughout the forest, the maple is much 
more dominant in the southern half and the elm in the northern 
half. In fact three-fourths of the hard maple and two-thirds of 
Fraxinus quadrangulata are in the southern half of the woods, 
while three-fifths of the elm, three-fifths of F. americana, and 
two-thirds of the blue beech (Carpinus) are in the northern half. 
It is the higher parts of the woods that are dominated by the maple, 
