ECOLOGICAL STUDY OF BRUSH LAKE. 153 
of Columbus. Probably the most important factor is the presence 
of Sphagnum, which is abundant in some parts of the Licking 
Reservoir. But why the Sphagnum should be abundant in the 
reservoir and entirely absent in Brush Lake is not so apparent. 
The general character and surroundings of Brush Lake are much 
the same as those of the ‘‘ Three Sisters.’’ 
For the present the writers will content themselves with a 
report of the conditions as found at Brush Lake, leaving gener- 
alizations to some future ecologist. No special work could be 
carried on in regard to physiological adaptations. In order to do 
such work it is necessary that one should be able to “ve with his 
plants for a considerable period of time. But ecological phyto- 
geography is still in its embryonic stage and it is perhaps better 
for the present to continue work more along geographical lines 
until better facilities are at hand for accurate and continuous 
observations on physiological adaptations. Besides, our present 
plant societies are being destroyed so rapidly that it is of primary 
importance that an historical record should be made. ‘This may 
be of the utmost importance in the future. 
THE PEANT, SOGH TIES: 
As stated above, the plant societies of the lake are arranged 
in concentric zones, as is usual where there is a gradual change 
in the environment. ‘The zones determined are as follows: 
Submerged Zone. 
Water-lily Zone. 
Half-submerged Zone. 
Decodon Zone. 
Uliginous Zone. 
Shrub Zone. 
Forest Zone. 
Da Ww No 
sy 
Of these, all may be regarded as normal except the uliginous 
zone, which toa large extent represents a recent society developed 
on the mud flats intercalated between the Decodon and shrub 
zones on the east and west sides of the lake. 
I. SUBMERGED ZONE. In this zone existence is almost 
entirely under water, for rarely do any of the plants composing 
it have even their tips extending above the surface. It is essen- 
tially a Potamogeton-Ceratophyllum-Myriophyllum-Chara zone. 
