THE NORTH TEMPERATE ZONE 



95 



Occasionally the big pink hollyhock flowers of the marsh mallow 

 (Hibiscus moscheutos) are seen, a flower belonging properly to the 

 salt marshes of the Jersey coast. Among the maritime plants that 

 have made their way to the shores of the Great Lakes, are the sea- 

 rocket (Cakile maritima) and the beach pea (Lathijrus maritimus). 



The northern forest area abounds in glacial lakes of all sizes. 

 The smaller lakes and ponds sometimes have been completely 



Fig. 20. — Deciduous forest, early spring, Rock Creek Park, Washington, D. C. 

 Oaks predominant; red-bud (Cercis Canadensis), and flowering dogwood, as 

 undergrowth. 



filled by the invasion of peat mosses (Sphagnum), and other bog 

 plants, and form swamps of greater or less extent, in which white 

 cedar or tamarack often form dense growths. These bogs arc the 

 home of many very beautiful plants, some of the finest orchids, 

 like the great pink lady's slipper (Cypripedium spectabilc) and the 

 exquisite Arethusa, Pogonia and Calopogon. Cranberries, An- 

 dromeda and other heath-like plants inhabit these bogs, as well as 



