LIFE HISTORY OF A MOSS 205 



bearing cells. Thus photosynthesis may be carried on, 

 though of course to a very limited degree. The sporo- 

 phyte of the true mosses seems to occupy an intermediate 

 position between those of Sphagnum and the fern, and, as 

 we ascend from the lower form in Sphagnum to the higher 

 form in the fern, the transition is largely characterized by a 

 decrease in the amount of fertile tissue and an increase in 

 the relative amount of sterile tissue of the sporophytes. 



FIG. 148. Protonemata of a moss bearing young gametophyte buds. 



190. Vegetative Multiplication. ^Extensive experiments 

 seem to indicate that every living cell of a moss-plant can 

 develop protonemata or in other words is a potential 

 spore. These protonemata like those produced by the 

 germination of spores, produce buds which may develop 

 into mature plants. The production of entire plants or 

 of parts of plants in this way, by portions of the vegetative 

 body, is called regeneration. In some species of mosses the 



