MOSSES. 163 



materials are passed from the gametophyte to the sporogonium. The upper 

 part continues to grow, and finally the upper end differentiates into the mature 

 capsule. 



343. Protonema of the moss. — When the spores of a moss germinate they 

 form a thread-like body, with chlorophyll. This thread becomes branched, 

 and sometimes quite extended tangles of these threads are formed. This is 

 called the protonema, that isjirst thread. The older threads become finally 

 brown, while the later ones are green. From this protonema at certain 

 points buds appear which divide by close oblique walls. From these buds 

 the leafy stem of the moss plant grows. Threads similar to these protonemal 

 threads now grow out from the leafy stem, to form the rhizoids. These 

 supply the moss plant with nutriment, and now the protonema usually dies, 

 though in some few species it persists for long periods. 



