1922] WATERMAN—PLANT COMMUNITIES 7 
and therefore not employing it to indicate any definite portion of 
the surface of the earth. There is an advantage in employing a 
special term for the ground occupied by each synecological unit, 
and the writer tentatively uses the word “‘locality” for the ground 
occupied by an individual association, “area”’* for that occupied by 
a formation, and ‘‘region”’ for that occupied by a formation complex. 
The present study is to be regarded as a preliminary reconnois- 
sance rather than as a completed work. Its purpose is to indicate 
the lines along which such a study should proceed, and to suggest 
some tentative conclusions. It is the intention of the writer to 
make a thorough study of the morphology and physiology of these 
communities, and in the light of those results to review the tentative 
conclusions now reached. This preliminary survey will also serve 
to introduce the region to ecologists, and to show the unusual oppor- 
tunity for the study of the very diverse communities of a region 
in relatively primitive condition. Incidentally the writer regards 
the region as one which should be included in a list of regions to be 
preserved in their natural condition. 
Description of habitat 
GrocraPHy.—The region is located in Benzie County, Michigan, 
and adjoins on the north the Crystal Lake Bar region already 
reported (10). It may be described as a right-angled triangle whose 
base is about eight miles long, extending south-southeast from a 
point on the shore of Lake Michigan about two miles northeast of 
Point Betsie, almost to the town of Honor on Platte River. The 
east side of the region is the perpendicular of the triangle, and 
extends north from ‘Honor nearly to the town of Empire on Lake 
Michigan. The shore forms the hypothenuse, curving slightly to 
the south with a projection at the mouth of Platte River. It hasa 
total area of about twenty-five square miles, of which perhaps one- 
fifth is occupied by lakes and ponds. The region is locally known 
as the Platte Plains, although it is composed of sand ridges and hills, 
and the general relief is distinctly rolling rather than flat (fig. 1). 
The Lake Michigan shore is bordered by a strip of moving dunes 
ranging from 200 to 500 yards wide. As the prevailing winds are 
* This is an ecological use of the term, and differs materially from its foristic use. 
