﻿190 Nichols: The vegetation of Connecticut 



Trichocolea tomentella Fissidens adiantoides 



Dicranum scoparium Thuidium delicatulum 



Georgia pellucida 

 The Relation of Swamp Forests to Upland Forests. — In relation 

 to the various plant societies of the lake-swamp series, the swamp 

 forest may be regarded as at least a temporary climax, although it 

 may not always represent the ultimate condition. So long as the 

 ground remains saturated with water throughout a great portion 

 of the year, it is manifestly difficult for a mesophytic flora to de- 

 velop. Yet very frequently seeds of white pine (Pinus Strohus) 

 and other trees from an adjoining upland germinate in a swamp 

 during periods of protracted drought, and once firmly established 

 these are sometimes able to persist in spite of unfavorable soil 

 conditions. Moreover, many upland mesophytes, like Tsuga 

 canadensis, Hamamelis virginiana, and Kalmia latifolia, are 

 commonly present in such swamps, growing on elevations of 

 various kinds. Through the extension of these elevations and the 

 formation of new ones, it is apparent that the general level of the 

 ground may become raised above the zone of saturation, so that 

 mesophytes will become more numerous and the swamp plants cor- 

 respondingly restricted. In this fashion it is perhaps conceivable 

 that a swamp forest might ultimately be replaced by a forest es- 

 sentially similar to that which marks the climax of succession on 

 uplands. Theoretically, at least, such a forest represents the 

 culmination of all hydrarch, as well as xerarch, successions in this 

 region. But, parenthetically, it must be conceded that while 

 upland mesophytes undoubtedly tend to become more and more 

 abundant in a lowland forest, and while the tendency for such a 

 forest to approach the upland type is unmistakable, nevertheless, 

 so rapid is decomposition under subaerial conditions, that it is 

 doubtful whether the substratum is ever raised sufficiently to 

 produce a truly mesophytic habitat through the operation of 

 biotic factors alone. 



Variations in the Rapidity of Succession in Lakes. — In the 

 foregoing paragraphs it has been shown that there is a tendency for 

 lakes and ponds to become filled in and converted into swamps 

 through the activity of vegetation ; but there are great differences 

 in the rate at which this transformation is brought about. Thus 



