April, 1908.] The Vegetation of Cedar Point. 303 



The Ulmus-Acer Forest Formation. 



Facies: Ulmus americana, 

 Acer rubrunt. 



Secondary Species: 



Fraxinus americana, Fraxinus lanceolata, 



Quercus velutina, Acer nigrum, 



Platanus occidentalis , Ostrya virginiana, 



Sainbucus canadensis, Rubus occidentalis , 



Rubus nigrobaccus , Ribes cynosbati, 



Parietaria pennsylvanica, Parthenocissus quinque folia, 



Lactuca -floridana, Inipatiens bi flora, 



Helianthus decapetalus, Phytolacca decandra. 



Solanuni nigrum, Galium triflorum, 



Boehmeria cylindrica, Botrychium virginianum, 



Campanula americana, Circaea lutetiana, 



Dryopteris spinulosa, Eupatorimn ageratoides. 



The accumulation of humus in the soil of the ridge as well as 

 the general rise of water in the Lake has brought about a gradual 

 change towards mesophytic, or even hydrophytic, conditions so 

 that this formation, as represented on Ridge No. 1, is practically 

 the same as would be the formation derived upon the filling up of 

 a hydrophytic pond or swamp by the accumulation of humus. 

 In either case there is a rich humous soil with great capillarity 

 and a high water table. 



The formation as represented on Cedar Point is not of large 

 area and it has, moreover, been much disturbed by man's acti- 

 vities, and no effort was made on the part of the writer to deter- 

 mine the minor formational structure. 



THE LAGOON-MARSH-WET MEADOW-THICKET-FOREST SUCCESSION. 



In the writer's studies on the ecology of Presque Isle there 

 was found to be represented there a remarkable series of lagoons, 

 these being evident in all stages from extreme youth to mature 

 old age, so that the successive development of "the lagoon vege- 

 tation w^as not difficult to decipher. On Cedar Point, however, 

 the lagoons are few and the successional series is rather incomplete. 

 Nevertheless, such stages as are in evidence show much similarity 

 to corresponding stages on Presque Isle so that, by correlation, 

 a fair idea may be gained of the probable structure of the lagoon 

 vegetation for the missing stages. 



For a lagoon or pond the normal tendenc}^ is to become filled 

 with accumulating vegetable debris, the surrounding vegetation 

 being arranged in concentric zones, each inner one more hydro- 

 phytic, and, with the accumulation of vegetable debris and the 

 elevation of the respective habitats, there is a continual advance 

 of all the zones towards the deeper central portion of the lagoon 



