Vegetation of Northern Cape Breton. 425 



lated by a very characteristic group of vascular plants, among 

 which the following are almost invariably present : 



Lycopodhim inundatum Drosera longifolia 



Rynchospora alba Vaccinium macrocarpon 



Eriophorum angustifoUum Vaccinium Oxycoccus 



Carex oUgosperma Bartonia iodandra 



Ranunculus Flammula reptans Utricularia cormita 



To this list might be added the curly grass fern {Schizaea), 

 which sometimes, and the bog rosemary {Andromeda), which 

 frequently is met with in situations of this sort. An important 

 ecological function is fulfilled by the sedges and the cranberries, 

 since through the medium of their roots and stems they reinforce 

 and bind together the mucky deposit, thereby producing a 

 semblance to floating mat formation. For convenience, a mat of 

 this sort, formed over a soft, mucky deposit, may be referred to 

 as a muck mat. 



Sphagnums of the semi-aquatic group, particularly 5. 

 pulchrum, frequently put in an appearance while the rising sub- 

 stratum is still covered by some depth of water. In such cases 

 the succession may be modified to such a degree that the muck 

 mat stage is omitted. For these semi-aquatic species, growing 

 in fairly dense masses, their stems erect and projecting slightly 

 above water level, are able to eliminate, probably through the 

 influence of shade, the lower, more truly aquatic sphagnums. 

 Associated with the sphagnums in such a habitat may grow, 

 locally in abundance, Scheuchseria, Eleocharis, Carex limosa, 

 Smilacina trifolia and Menyanthes. These may fulfill here a 

 function similar to that performed by sedges and cranberry in 

 the case of the muck mat, where also they are not infrequently 

 represented. 



Returning to the consideration of the muck mat : the sphagnums 

 of the aquatic group are incapable of building up the surface to 

 any appreciable height above ordinary summer water level, 

 although to a limited extent this may be accomplished by the 

 sedges. Further elevation is dependent primarily on the advent 

 of the more mesophytic sphagnums. For some reason, the 

 prostrate, felty tangle of aquatic sphagnums and Cephalozia, 

 which commonly covers the surface of the muck mat, seems to 

 hinder the rapid establishment of other bryophytes, and in 



Trans. Conn. Acad., Vol. XXII 24 1918 



