﻿Nichols: The vegetation of Connecticut 



the water level rises correspondingly, with the result that the roots 

 of plants originally growing on the mat's surface are submerged. 

 The characteristic plants of Sphagnum Bogs are those which are 

 able in some way to develop root systems above this zone of 

 saturation. Species like Aspidium Thelypteris and many sedges 

 accomplish this result through the upward growth of their rhi- 

 zomes. Sprawling vines like Chiogenes and Vaccinium macrocar- 

 pon similarly have little difficulty in establishing fresh footholds 

 from time to time. The pitcher plant possesses little power of 

 stem elongation and individual plants are buried quite rapidly, 

 but like some other bog plants it reproduces itself with sufficient 

 rapidity by means of seeds to enable it to hold its own. Among 

 the shrubs the most successful species are those which freely 

 produce adventitious roots from the old upright stems above the 

 zone of permanent saturation. Among others, Chamaedaphne, 

 Kalmia polifolia, and Ledum are noteworthy in this respect. In 

 a specimen of Ledum, for example, which the writer collected in a 

 Sphagnum bog at Norfolk, the leafy shoot rose but eight inches above 

 the surface, the remaining part of the stem, more than three feet long, 

 being imbedded in the moss. Adventitious roots had developed 

 throughout the length of the stem, those on the first foot of stem 

 below the surface being vigorous and obviously the only ones 

 functional at the time of collection. It is interesting to note in 

 this connection that Cowles,* in his study of the vegetation on the 

 sand dunes of Lake Michigan, found that the ability of many 

 woody plants to withstand burial by sand likewise depends on their 

 power of stem elongation plus the development of adventitious 

 roots. The upward growth of a Sphagnum cushion proceeds 

 most rapidly at first; eventually it attains a height where the 

 balance between increasing evaporation and decreasing water supply 

 is such that further upward growth is no longer possible. When 

 this stage is reached species of the lichen Cladonia and relatively 

 xerophytic mosses like Polytrichum commune and Hypnum 

 Schreberi frequently establish themselves on top of the Sphagnum 

 cushions. 



The Significance of the Marginal Ditch.— -Separating the bog 

 from the adjoining upland, more often than not, there is a broad, 



