SUCCESSIONS IN BOGS 33 



istic of flat areas and along shallow shores. The type of peat 

 is firm, finely fibrous and felt-like in appearance. It retards 

 drainage, and in rainy seasons retards the run-off. As the water 

 level becomes continuously raised with the accumulation of the 

 dominant growth, a peat bed is built up from the bottom of the 

 successive elevations of the water level. Since these conditions 

 eliminate many species of hydrophytic plants, the peat is usually 

 homogeneous in texture. The flora of a deposit of that character 

 becomes heterogeneous only when the water level remains high 

 or low for a long time. Sedge bogs are relatively rare and no 

 longer typical in Ohio. 



B. The bog heath associations 



No matter how numerous the seeds or fruits brought in by 

 wind, birds, or other agencies, effective establishment is possible 

 only to the few plants in which there is some sort of correspondence 

 or balance in plasticity of function or in habitat form to the life- 

 relations in the peat substratum. The soil processes are best 

 expressed in terms of reduction action. The pioneer invaders 

 are at first isolated, but mass invasion is not infrequent upon 

 transition areas and tension lines. The distribution of bog heaths 

 is, however, far more limited than that of any other of the associa- 

 tions in the cycle. This is largely due to the greater specializa- 

 tion in habitat requirements. Other plants are excluded for 

 the reason that they can not subsist on the organic compounds 

 arising in the substratum. 



1. Chamaedaphne calyculata association. With few excep- 

 tions the association is limited to and more typical in the north- 

 eastern portions of Ohio. The botanical composition of the 

 vegetation structure is relatively uniform; Chamaedaphne caly- 

 culata in low but dense and almost impassable thickets, with 

 Andromeda polifolia and Gaylussacia baccata as principal species. 

 Several ferns (Osmunda cinnamomea, 0. regalis) and Rubus 

 setosus are frequent where the cover is scattered and more open. 

 The ground layer consists of sphagnums and polytrichum over- 

 grown with Rubus hispidus. 



