3IO The Ohio Naturalist. [Vol. VIII, No. 6, 



of the fades into definite structures the Cephalanthus occiden- 

 talis Consocies occupies the part of the habitat adjoining and 

 grading into the Decodon-Persicaria habitat, while the other two 

 facies alternate with each other in the outer more mesophytic 

 part of the habitat. The formation is here bordered by a shrub 

 formation which is approaching old age and which mav more 

 properly be regarded as a bordering thicket associated normallv 

 with the Calamagrostis Wet Meadow Formation. 



The Rhus hirta Thicket Formation. 



Facies: Rhus hirta. 



Secondary Species: 



Cornus amomum, Cornus stolonifera, 



Salix cor data, Salix nigra, 



Salix amygdaloides, Salix lucida, 



Vitis vulpina, Parthenocissus quinquefolia, 



Dryopteris thelypteris, Rubus nigrohaccus. 



This formation apparently displaces the Salix {spp.) Forma- 

 tion where dryer and more mesophytic conditions are approached. 

 This also represents a consocies of a more northern formation 

 which on Presque Isle was of considerable importance and was 

 there designated as the Rhus-Alnus Thicket Formation. 



The Ulmus-Acer Forest Formation. 



There are evidences that this formation will come in instead 

 of the Quercus velutina-imhricaria Forest Formation in the zone 

 first occupied by the Populus-Salix Formation. The elevation 

 of the water table and the consequent hydrophytic tendency of 

 this habitat probably has something to do with the exclusion of 

 the oak forest from this zone. Where the cotton-woods have 

 ■built up a steep ridge in close proximity to the water, as on the 

 ■east side of the Lily Pond, the vegetation will, of course, be more 

 xerophytic and will follow the stages as indicated for the ridge 

 ■succession, finally passing into the oak forest and this will not 

 pass into the Ulmus-Acer forest until considerably more meso- 

 phytic or even semi-hydrophytic conditions prevail by the 

 accumulation of much humus or by the rise of the water table, 

 or both. 



To the southwest of this pond there is a small narrow pond 

 almost choked up with vegetation, the whole being somewhat 

 further developed in its successional stages. The Cephalanthus- 

 Cornus Thicket Formation is strongly developed and, in the 

 course of a few years, unless the rise of the water is too rapid, 

 the shrubs will have occupied the whole central portion of the 

 depression. 



Previous to the construction of the artificial canals or "La- 

 goons" in connection with the amusement features of the pleasure 



