INTRODUCTION 9 



are more numerous than the liverworts and are divided 

 into three Orders: I. Sphagnales, or peat mosses; 

 II. Andreaeales; III. Bryales, or true mosses. The first 

 two Orders are described in separate chapters, as they 

 differ in structure from the true mosses. See Sphag- 

 nales (p. 73) and Andreaeales (p. 75). 



The reproduction of mosses is accomplished in two 

 general ways, sexually and asexually. In the asexual 

 or vegetative reproduction, that is, multiplication by 

 other means than by the sexually formed s pores, either 

 small organisms, known as ''gemmae," produced 

 among the leaves or at the end of slender branches, 

 become separated from the parent plant and develop 

 new individuals, or parts of the plants, such as bits 

 of the stem, branches, or leaves, become detached and 

 grow into new plants. In the sexual reproduction, 

 mosses, like ferns, start from a spore, not from a seed. 

 The spore first produces a green thread-like growth 

 called protonema, and upon this a tiny bud develops 

 that grows into the leafy plant. The male and female 

 flowers occur at the apex or on the side of the stems 

 and branches, sometimes growing on the same plant 

 and sometimes on separate plants. The sexual organs 

 are microscopic, but the male buds are often conspicu- 

 ous and surrounded by a rosette of bract-like leaves 

 that are green, red, or orange. The sperms from the 

 male flowers swim in moisture, after rains or heavy 

 dews, to the egg-cell of the female flower. After fertili- 

 zation takes place, the fruit or capsule develops, en- 



