﻿Nichols: The vegetation of Connecticut 201 



devoid of mechanical tissue, could hardly be expected to possess 

 any great degree of tensile strength. Moreover, as a rule. Sphag- 

 num does not develop in any abundance until a later stage in the 

 succession. Various species of Drepanocladus may also grow in the 

 water about the Decodon roots, but their role in mat formation is in- 

 consequential. As in the case of the sedge mat earlier described, 

 it is the vascular plants with their tough stems and roots, partic- 

 ularly species like the cranberry (Vaccinium macrocarpon) and 

 Cassandra {Chamaedaphne calyculata), which are primarily re- 

 sponsible for the increase in the continuity and compactness of 

 the substratum. Decodon is primarily a pioneer, and in competi- 

 tion with other plants is speedily exterminated. When present, 

 it usually occupies a zone from six to a dozen feet wide along the 

 water front, but, except for scattered specimens, is absent else- 

 where. Inside the Decodon zone there is commonly a zone dom- 

 inated by Cassandra, along with which, in increasing abundance, 

 grows the Sphagnum. 



It might naturally be anticipated that where the pioneer 

 plants are shrubs, the sedges would be eliminated from the 

 succession, but this is rarely the case. Almost always sedges 

 and other herbaceous bog plants occur in among the shrubs, 

 and quite frequently the cassandra zone is bordered on the land- 

 ward side by a more or less continuous zone in which the domi- 

 nant plants are Sphagnum, cranberries, and such sedges as 

 Rynchospora alba and Eriophorum virginicum. The exact ex- 

 planation of this last mentioned phase in the succession is puzzling. 

 It seems to represent a Retrogressive Condition due to some 

 disturbance which has caused the disappearance of the cassandra 

 and has thus created an opening for a more primitive association to 

 become established. Such a result might be effected either by a 

 sinking of the mat, or by a temporary elevation of the water level 

 which might flood the grounded portions of the mat, and, if of 

 sufficient duration, might cause the death of the cassandra. Pro- 

 ceeding farther landward from this zone, shrubs once more assume 

 control, and under normal conditions, as in other cases, trees 

 ultimately become the predominating element of the vegetation. 



There are other ways in which the formation of a floating mat 

 may be inaugurated. At Bingham Pond, Salisbury (Fig. 14), and 



