100 Proceedings of Indiana Academy of Science 
side, however, is composed almost wholly of three species: Andropogon 
virginiana (Fig. 8), Solidago odora, Gymnolmia Porteri (Fig. 9). 
Ill. The Mixed Forests on the East and West Sides. 
On these areas there is a general mingling of the north side vegeta- 
tion with that of the south, but in this mingling there is a notable 
absence of certain of the north talus species and the occurrence of cer- 
tain species not found on the north or south. 
Pycnanthemum albescens. Amorpha virgata (small). 
Liatris polyphylla. - Prunus Persica. 
Eupatorium capillifolium (Fig. 10). Hypericum prolificum. 
are species more or less peculiar to the east and west sides. 
SUMMARY. 
In the study of plant ecology on Stone Mountain, certain rather 
remarkable conditions have been noted. 
1. The north side is a vertical unbroken wall whose face is beveled 
toward the summit, and is only partially covered with lichens, its only 
form of vegetation. 
2. The rich narrow talus on the north, which must have been 
formed by a very remote falling of granite fragments from the sum- 
mit, bears a dense forest of broad-leaved trees with a typical herbace- 
ous association, 
3. The south side surface stands at an angle of about 45 degrees 
and is sparsely overgrown with conifers and flowering herbs. 
4. The broad talus on the south is covered by a pure stand of 
pine merging into a mixed forest toward the outer margin, where are 
found many broad-leaved deciduous species, as oaks, hickories, tulip, 
sweet gum, black gum, and a herbaceous formation approaching in 
character that found in a pure regional deciduous forest. 
5. The east and west slopes seem to be a mean between the steep 
north side and the gradual south side, and the east and west floras are 
partial blends between the north and south floras. 
CONCLUSIONS. 
1. A steep north side and a gradual south side have been made 
possible by certain conditions of the past, viz., differential exposure to 
the sun’s rays, prevailing winds, and proximity to major streams. 
2. The same conditions that have produced a physiographic dis- 
tinction between the north and south sides have also made possible a 
floral distinction. 
3. The physiographical and vegetational aspects of the east and 
west are but natural blends between the extremes of the north and 
south. 
Purdue University. 
