CHE 
BoA SICAL. CGAZETTE 
JULY ort 
THE VEGETATION OF CRANBERRY ISLAND (OHIO) AND 
ITS RELATIONS TO THE SUBSTRATUM,-TEMPERA- 
TURE, AND EVAPORATION." I 
ALFRED DACHNOWSKI 
(WITH SEVEN FIGURES) 
The object of the present paper is to give, as briefly as is con- 
sistent with a limited presentation, the major conditions of some 
of the factors which have been found limiting the activity of 
plants in bogs. 
The striking discontinuity of bogs in distribution, the absence 
of genetic relationship between bog plants and the surrounding 
flora of states in the latitude of Ohio, and the floristic agreement 
of these plants with the vegetation of the distant north has invited 
the attention of many students of ecology. 
As early as 1872 a solution of this interesting problem had been 
formulated by Gray (14) in his glacial relict theory. A similar 
explanation has been advanced by numerous recent writers, and 
the broader relations which involve comparative studies have 
been well established (31). However, the reciprocal relations of 
these plants and their habitat, the demands which the plants make 
on their environment, the means which they employ, and the 
functional réle which the particular species perform; in short, an 
investigation of factors by which the present associations are 
determined and which would account for the existence and the 
peculiarities, structural and functional, of these ‘‘boreal” plants 
* Contribution from the Botanical Laboratory, Ohio State University, no. 61. 
I 
