MetapJiyta Polytridtum. 



i ii 



From this intermediate thallus the true thallus springs as a 

 lateral outgrowth. The mode of development and the 

 varieties of form observable among 



i ji i FIG. 42. Fontinalis 



protonemata cannot be dealt with in antipyretic*. - PERIS- 

 the present volume. The thallus ori- 

 ginates from the subdivision of a single 

 cell of the protonema, which may be 

 termed an apical cell since it, or a 

 descendant of it, retains its apical posi- 

 tion, and by its subdivision increases 

 the length of the shoot. 



Having gone over briefly the struc- 

 ture and life-history of a typical moss, it may be well by 

 way of summary to follow the plan adopted at the end of 



FIG. ^.Funaria kygrometrica. (Sachs.) 



A. germnatng spores XSSQ); s, exosporium ; w, root hair ; v, yacuole. B, part of 

 protonema three weeks after germination ( x QO) ; h. main branch ; ^, side 

 branch ; /i, formation of a bud from which the stem of the moss arises. 



the preceding sections, and give a short comparison of the 

 stages in the life-history of the moss with those of the lower 

 types already discussed 



