Mosses and Lichens 



the side walls break down, then an inner row of teeth or cilia 

 will be formed. All the varied forms of teeth are determined by 

 the portions of the cell-walls which remain. 



Upper part of 

 epore-case with 

 four teeth. 



Cross-section of the four teeth 

 to show their solid nature. 



Georgia pellucida. 



Tayloria splachnoidts. Colum- 

 ella attached to the base of the 

 spore-case. 



In the genus Georgia, after the outer layer of the upper part 

 of the spore-case has fallen away as a lid, the whole inner layer 

 splits into four triangular valves which form the teeth. 



Portion of peristome to show 

 Summit of Spore-case Spore-case a s i ng ie row of teeth, 



spore-case. without lid. with lid. 



Tetraplodon mnioides. To show a single row of teeth in pairs. 



In Fontinalis antipyreiica the inner peristome forms a lattice 

 work due to the breaking down of the inner cell-wall faces and 

 the retention of the side walls. 



The columella of many mosses shrivels up and disappears 



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