Leafy Mosses 



spaces between the teeth open into the spore-case and through 

 them spores may escape. 



THE PEDICEL OR SETA 



The seta has undoubtedly been developed for the purpose of 

 raising the spore-case to a height where the spores may be most 

 advantageously scattered. In many mosses the seta becomes 



ua 



illicit 



Catharine a undulata. 

 Summit o f spore-cast 

 with thirty-two teetj. 

 attached to the epi 

 phragm. 



Buxbaumia aphylla. 

 Sporophyte. 



Ulota crispa. 



Fuaariahygrontetrica. Cross-section 

 of seta. 



abruptly larger just below th 

 spore-case to form an apophysis. 

 This may be long and cylindrical, 

 or of many other forms. In the 

 Polytrichum mosses it is a more 

 or less flattened disk. 



The seta is surrounded at the 

 base by a sheath which is the 

 vaginule and may be the remains 

 of the base of the archegonium. 



The pedicels (setce) have vari- 

 ous methods of twisting or turn- 

 ing while growing so as to bring 

 the developing spore-case into 

 positions most favourable with 

 reference to light and moisture. 



57 



