Vegetation of Northern Cape Breton. 329 



attributable to the erosive effect of wind-driven snow in winter, a 

 phenomenon which will be referred to again in connection with 

 the vegetation of the barrens. 



Wherever a shingle beach borders en the mainland, there is 

 a tendency for the forests of the adjoining upland to encroach 

 on the beach (Fig. 27), and even on barriers and spits scrvibby 

 forests are frequently developed on the older parts of the upper 

 beach (Fig. 29), usually on lea slopes where there js optimum 





Figure 29. — Stunted balsam firs (foreground) and scrubby forest (left 

 background) on shingle beach; St. Ann's Bay; compare Fig. 33. 



protection from wind and wave. Such forests are quite open, 

 and are composed almost wholly of white spruce and balsam fir, 

 which seldom reach here a height of more than twenty-five feet. 

 In the open spaces between the trees grow in more or less pro- 

 fusion various of the shrubs and herbaceous plants which have 

 been listed as occurring on the upper beach, while certain less 

 xerophytic species, which have been cited earlier as characteristic 

 of the pioneer forest stage in the ordinary upland series, are 

 found here also. Common bryophytes in the shade of the trees 

 are Ptilidium ciliare, Dicranum Bonjeanii, Dicraniim undulatum, 

 Trans. Conn. Acad., Vol. XXII 21 1918 



