158 W. S. Cooper 



miles beyond the present southern Umit of the species (Chaney 

 and Mason, 1933). 



A number of genera including Glehnia, formerly combined 

 under Cymopterus, have their homes almost exclusively in w^est- 

 ern North America. Their united ranges extend from western 

 Missouri to the Pacific Coast and from southern Canada to 

 northern Mexico (Mathias, 1930). Glehnia is the only one that 

 transgresses the boundaries of this region. 



Convolvulus soldanella L. (fig. 6g) is an important species of 

 the foredune zone; it binds surfaces effectively but does not form 

 hillocks. Its range on the Pacific coast of North America is from 

 Vancouver Island (Ucleulet) southward to the Mexican bound- 

 ary and perhaps beyond. This species has by far the widest dis- 

 tribution of our entire list; it is found upon the coasts of all the 

 continents except Africa. It occurs in western Europe upon the 

 British Isles, the mainland shore of the North Sea, the Atlantic 

 coast of France, and in the northwestern part of the Mediter- 

 ranean; in Japan, Manchuria, China, the East Indies, Australia, 

 and New Zealand; and on both coasts of southern South 

 America. 



The Convolvulaceae as a whole are a tropical family and are 

 especially well developed in Asia and America. Convolvulus 

 soldanella represents a genus that is not typically coastal, but 

 well distributed over the temperate and subtropical parts of all 

 continents (Peter, 1897). 



Mertensia maritima (L.) G. Don (figs, ^c, 5^) is strictly a 

 strand plant, almost exactly equivalent to HoncJ^enya peploides 

 in habitat preference. In southward extension along the Pacific 

 coast of North America it is the most restricted of the group of 

 northern littoral species. Its known range ends at the Queen 

 Charlotte Islands. In general distribution it is very similar to its 



