Vegetation of Northern Cape Breton. 333 



On the lea slopes of these low dunes, trees germinate, pre- 

 dominantly white spruce, but some balsam fir. The reciprocal 

 relation between these trees and the dunes is rather striking. 

 Germinating in the first place in the shelter of the low dunes, as 

 the trees increase in size they afford an effective wind-break, 

 which in turn is largely responsible for the further increase in 

 the height of the dunes. The bases of the trees may be covered 

 to a depth of six feet or more by sand, but both the spruce and 

 the balsam are able to accommodate themselves to the changed 

 conditions through the development of adventitious roots from 

 the buried part of the trunk. The highest dunes are covered 

 at the crest with good-sized trees which have thus been partially 

 buried. 



The dunes very likely would attain a greater height here, were 

 it not for the fact that they are exposed to winds from two 

 directions ; the westerly winds which sweep across the pond 

 tend to check the growth of the dunes, which is due mainly to 

 the easterly winds from off the ocean. 



In the lea of the dunes, between them and the salt meadows, 

 is a broad stretch of low, sandy "back beach," the surface of 

 which is rolling, and is covered partly by an open coniferous 

 forest, partly by grassy areas with scattered trees. Below is 

 given a list of the vascular plants, exclusive of certain weeds, 

 which occur more or less abundantly in these open tracts. 



Jimipcrus communis depressa Fragaria virginiana 



Panicum implicatum Potcntilla tridentata 



Agrostis alba maritima Lcchca intermedia juniperina 



Danthonia spicata Vaccinium Vitis-Idaea 



Festiica rubra Campanula rotundifolia 



Arenaria lateriflora Leant don autumnalis 



The grassy sward is nowhere very close, but the sand is 

 nearly everywhere hidden by the two mosses, Tortula ruralis and 

 Dicranum spurium, and species of Cladonia. In among the trees 

 occur a number of species which were not noted in the more 

 open situations, or only rarely so, such as Maianthemum 

 canadense, Trientalis americana, Rhus Toxicodendron, Ribes 

 lacustre, and the mosses, Dicranum nndulatum and Hypnum 

 Schrcberi. The branches of some of the white spruces support 

 the most luxuriant growth of the dwarf mistletoe (Arceuthobium 

 pusillum) that the writer has ever seen. 



