Vegetation of Northern Cape Breton. 421 



formation are usually absent or poorly developed. About the 

 only form at all abundant is 6^. Pylaisci, a rather delicate species 

 which, with the liverwort, Cephalosia fluitans, commonly covers 

 the peaty substratum in among the sedges with a thin, felty mat. 

 At an early stage in its development, in addition to the sedges 

 already mentioned, the vegetation of such an association-type 

 includes, among others, the following species : 



Schizaea pusilla Rynchospora fusca 



Lycopodium inundatum Bartonia iodandra 



Scheuchzeria palnstris Drosera longifolia 



Scirpus caespitosus Vaccinium macrocarpon 



Rynchospora alba Utricularia cornuta 



As time goes on, Scirpus caespitosus, at first scattered, comes 

 to occupy the ground more and more completely, forming a 

 rather dense sward and crowding out most of the species listed 

 above, except such as are able to persist in local depressions. 

 The Scirpus is responsible for a still further elevation of the sub- 

 stratum, but the peat in such a swamp is almost invariably 

 shallow, seldom exceeding two feet in thickness. Commonly 

 associated with the Scirpus in this association-type are the fol- 

 lowing : 



Calamagrostis canadensis Epilobium palustre 



Carex Michanxiana Drosera rotundifolia 



Carex pauciflora Sarra-cenia piirpurea 



Habenaria blephariglottis Aster nemoralis 



The vegetation is predominantly herbaceous, with Scirpus as 

 the character plant. As a rule, however, there is a scattering of 

 low shrubs, such fonns as Myrica, Spiraea, Andromeda, 

 Chamaedaphne, Kalmia polifolia. Rhododendron, and Lonicera 

 caerulea, which, along the shoreward margin, commonly form 

 a thicket. An association of this sort bears a marked resemblance 

 to bog-meadow, as described later in connection with raised 

 bogs. In many situations it seems without question to represent 

 an edaphic climax. Failure for succession to proceed further is 

 probably correlated with an inability on the part of the cushion- 

 forming sphagnums to gain control, an inability for which the 

 periodic inundation seems in some way to be responsible. 



