332 The Ohio Naturalist. [Vol. VIII, No. 6, 



ditions as would indicate a possible Ulmiis-Acer zone as a succes- 

 sor to the shrub zone providing other conditions do not prevent 

 their development. However, if the trend of environmental 

 conditions is to continue indefinitely as in the past there is little 

 probabilitv that this forest zone will be able to'mature. 



The Cove Habitat. 



The Cove Habitat and its vegetation is one of the most 

 marked ecological features of Cedar Point. The completeness 

 of the vegetational structure and the size of the habitat, as exem- 

 plified in Biemiller's Cove and in other coves to the south of the 

 Laboratory, are far in advance of anything in this Hne at Presque 

 Isle and to say the least, the student of cove vegetation will find 

 here exceptionally fine opportunities for such studies. Proceed- 

 ing from the deepest water towards the shores the general struc- 

 ture of the vegetation may be classified as follows: 



a. (The Chara Formation.) 



b. The Potamogeton Formation. 



c. The Castalia-Nymphaea Formation, 



d. The Phragmites-Typha Marsh Formation, 



e. The Calamagrostis canadensis Wet Meadow Formation, 



f. The Cephalanthus-Cornus Thicket Formation, 



g. The Rhus hirta Thicket Formation, 

 h. The Ulmus-Acer Forest Formation. 



The Chara Formation. 



A few specimens of Chara w^ere found at Piesque Isle in situa- 

 tions similar to the Cove Habitat at Cedar Point and Pieters 

 reports more or less complete Chara associations in the western 

 end of Lake Erie and in Lake St. Clair, although seldom found 

 where the bottom was sandy .^^ Probably with proper facilities 

 a search of the coves of Cedar Point would reveal a more or less 

 well developed Chara formation; although generally sandy, the 

 cove bottoms are not altogether so. 



The Potamogeton Formation. 



This formation is particularly well developed here and, in 

 general, it very closely resembles the corresponding formation 

 at Presque Isle. Its habitat may be said to comprise that part 

 of the cove in which the water is four feet or more in depth, ex- 

 cepting in the deepest portions w^here the Chara Formation may 

 be more characteristic. The coves are likely nowhere so deep as 

 to exclude the latter formation. The structure of the Potamoge- 

 ton Formation is essentially as follows: 



21. Pieters, A. J. The Plants of Western Lake Erie with Observa- 

 tions on their Distribution. U. S. Fish Commission, BulL 1901 : 57-79. 

 and The Plants of Lake St. Clair. Bull. No. 2, Michigan Fish Commission, 

 1894. 



