April, 1908.] 
The Vegetation of Cedar Point. 
3 1 7 
cussed. The final decision as to the influences determining 
whether the one or the other phytogeographical element shall 
predominate must be deferred until exact instrumental deter¬ 
minations may have been made of the various environmental 
factors in the different parts of the Sand Plain, but, if an opinion 
may be here ventured, it seems probable that the ecological con¬ 
ditions are so nearly equally suitable for the two elements that 
historical considerations become of prime importance, and that 
a very slight fluctuation of the ensemble of ecological factors 
from one direction to the other may be sufficient to determine 
which vegetation shall gain the ascendency. 
The vegetation of the Bar Section, as so well described by 
Moseley consists almost entirely of the Artemisia-Panicum Sand 
Plain Formation, there being on the Bay side a narrow strip of 
more hydrophytic vegetation just at the edge of the marsh. 
The whole bar is shifting over onto the marsh and it appears 
likely that the conditions do not reach such a state of stability 
as to permit the development of a well market thicket stage. 
Instead of an outward growth of che land form towards the Lake 
there is here exactly the opposite taking place and the real suc¬ 
cession of habitats is abnormal, being from marsh through sand 
plain to beach. 
At the south end of the small peninsula between Biemiller’s 
Cove and the Bay there is a small area of the Artemisia-Panicum 
Formation, but there is no very well marked area of sand plain 
of any considerable size in the Dune Section, small areas being 
scattered here and there between the dunes and blow-outs and 
in the oak forest. Between the Dune Section and the Ridge 
Section are limited areas of a thicket stage which may be called 
the 
Rhus-Prunus-Toxicodendron Thicket Formation. 
The apparent facies being: 
Rhus aromatica, 
Prunus virginiana. 
Toxicodendron pubescens. 
This thicket formation is soon followed by the 
Quercus velutina-imbricaria Forest Formation, 
this having here essentially the same structure as described for 
the Ridge Succession. The thicket formation succeeding the 
Artemisia-P anicum Formation on Cedar Point is not nearly so 
prominent or vigorous a structure as is the corresponding Myrica 
Thicket Formation of Presque Isle. 
Taking up now the succession of northern phytogeographic 
affinities we have, as follows: 
