THE KEYS EXPLAINED 



The object of the Keys is to give the student a non- 

 technical guide to the genera and in some cases the 

 species of the mosses he is likely to notice, and to en- 

 able him to recognize them without the aid of a lens. 

 No preliminary knowledge of the mosses is necessary 

 except of their habitat; that is, the natural locality of 

 the plants, as ground, rocks, trees, etc. The numbers 

 in the Keys refer to the genera in ''List of Genera" 

 (p. 70). Illustrations of the descriptive terms used will 

 be found on Plates I, II, III, IV. 



Two separate Keys are provided, each including all 

 the mosses described in the book. The Leaf Key is 

 based upon the character of the leaves with further 

 subdivisions, and the Capsule Key is based upon the 

 character of the capsules with further subdivisions. In 

 some cases the leaves alone or the capsules alone are 

 not sufficient to determine a moss, and for this reason 

 the Leaf Key is carried out with capsules and the Cap- 

 sule Key is carried out with leaves. Stem characteris- 

 tics are given when helpful in dividing the mosses into 

 groups. The length of the stem is measured from the 

 rootlets through the leafy portion; but does not include 

 the fruit-stalk. (See Plate I, Fig. i.) 



In both Keys the mosses are first divided in the usual 

 way. Division A including the acrocarpous mosses with 



