lo HOW TO KNOW THE MOSSES 



closing the spores. The capsule is usually borne above 

 the plant on a stalk of varying length, called the seta. 

 When the seta is very short or lacking, the capsule is 

 almost hidden in the surrounding leaves. At the mouth 

 of the capsule are special parts that serve to protect the 

 spores until they are mature and ready to be scattered 

 to develop new plants under favorable conditions. 



As special reference is made in the Keys to the char- 

 acter of the capsule, leaves, and stems, they are de- 

 scribed in chapters by themselves. (See "Habit and 

 Manner of Growth," p. 12, ''Leaves," p. 15, "Cap- 

 sules," p. 20.) 



Some mosses are short-lived, but many are peren- 

 nial, and continue their growth annually at the tips of 

 the stems and branches, or develop new plants from 

 underground stems. There are no true roots, but the 

 plants are attached to their substratum by radicles, or 

 rootlets. Radicles are not only at the base of the stem, 

 but sometimes cover the greater part of it, forming a 

 brown or whitish, felt-like coating, called tomentum. 



The simple structure of mosses enables them to ab- 

 sorb moisture easily, and where extensive growths 

 occur, they perform an important service to plant-life 

 by holding back much of the rainfall, allowing the 

 water to soak into the earth gradually instead of 

 running off the surface. They also add to the rich- 

 ness of the soil through their decay, and assist in the 

 disintegration of rocks. A few of the larger species 

 are used as a packing material. Sometimes they are 



