Vegetation of Northern Cape Breton. 401 



of hills (Figs. 51, 52), and in general prevails on well-drained 

 uplands wherever the conditions of exposure are such as to pre- 

 vent the development of a more mesophytic type of vegetation. 

 At first sight an area occupied by this association-type appears 

 as a crowded, labyrinthine series of low movmds or hummocks, 

 irregular in size and shape, but averaging perhaps from three to 

 ten feet in diameter by from one to two feet in height. The 

 hummocks are densely overgrown with cladonias and support a 

 thick growth of low shrubs, mostly ericads. Depressed, bushy 

 trees, mainly black spruce, scarcely two feet high but spreading 



Figure 52.^Dwarf shrub-spruce heath ; barrens in mountains west of 

 Ingonish. 



out laterally over a radius of several feet, constitute an important 

 element in the vegetation, growing on or alongside the hum- 

 mocks. Here and there, scattered tamaracks may be conspicu- 

 ous by reason of the fact that they project somewhat above the 

 general surface level of the surrounding vegetation, which 

 otherwise maintains a nearly uniform height at from two to two 

 and a half feet above the floor of the depressions which separate 

 the huminocks. In typical dwarf shrub-spruce heath, the 

 depressions between the hummocks are open and, aside from the 

 cladonia mat which nearly everywhere covers the ground, their 

 vegetation is scanty. 



The following list includes the more characteristic plants of 

 dwarf shrub-spruce heath : 



