Chap. VII] COLD TEMPERATE FOREST FORMATIONS 567 



grow within a few feet of one another. The ground is covered by a dense 

 soft carpet of mosses and ferns, frequently of extraordinary size. Well- 



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o 



lighted spaces are filled with impenetrable thickets of various shrubs, in 

 which almost tree-forms of Vaccinium, species of Corylus, and Acer circina- 

 tum play the chief part. This forest owes its extraordinary luxuriance to 



