X EXPLANATION OF THE PLATES. 



Fig. 8. Section of upper part of sporangium of Bartramia fontana, 

 magnified (after Lantzius-Beninga). 



c. columella. 

 s. spore-sac. 



a. outer wall of spore-sac. 



*. intermediate space, traversed with threads. 



m. inner wall of intermediate space. 



k. outer wall of intermediate space. 



I. row of cells continued from m. 



g. row of cells continued from top of intermediate space. 



d. inner peristome, formed from the thickening of the outer 



wall of the cells in I and the inner wall of the cells in g. 

 h. row of cells continued from outer wall of intermediate 

 space. 



b. outer peristome, formed by the thickening of the outer 



wall of the cells in g and of the inner wall of the cells 

 in h. 



PLATE II. 



1. Sphagnum cymbifolium. 



. plant, nat. size. 



b. cells from stem, magnified. 



c. leaf, magnified. 



d. sporangium. 



2. S. compactum. 



a. plant, nat. size. 



b. cells from stem, magnified. 



c. leaf, magnified. 



d. sporangium. 



3. S. molluscum. 



a. plant, nat. size. 



b. cells from stem, magnified. 



c. leaf, magnified. 



