THE KEYS EXPLAINED 25 



leaves are large enough to show the entire outline when 

 the plants are held to the light, the mosses are placed 

 under the next corresponding head, ''Shape of leaves 

 when moist easily seen." In Division B the mosses are 

 divided a little differently, as the leaves vary less in 

 shape and in many cases the entire outline is not so 

 necessary in determining the genera. When the leaves 

 are large enough to show whether they are straight or 

 curved, the mosses are placed under ''Leaves when 

 moist easily seen " ; when the leaves are too small or too 

 closely folded to show this characteristic, the mosses 

 are placed under "Leaves when moist not easily seen." 

 In both the Leaf Key and the Capsule Key the posi- 

 tion and the shape of the capsule that are given are 

 always those of the fully developed fruit. In order to 

 recognize when the capsule is mature see chapter on 

 "Capsules " (p. 20). 



