BEITISH MOSSES. 



P 



FIG. 27. Leaf of Sphag- 

 num acutifolium, magni- 

 fied ; * s, stem ; p, point 

 of the leaf. After Schim- 

 per. 



the foregoing description. Fig. 

 27 shows a magnified leaf of 

 the Sphagnum acutifolium with 

 a portion of the adjoining stem 

 (s s), of which more hereafter. 

 The edges of the leaf are turned 

 over as may be seen by looking 

 at the extreme point of the leaf 

 (/>) where these foldings over 

 cease. Fig. 28 exhibits a portion 

 of a leaf far more highly magni- 

 fied ; the large cells free from 

 chlorophyll bounded by the 

 narrower cells charged with it 

 will be at once observed as well 

 as the spiral threads developed 

 on the walls of the larger cells, 

 a peculiarity of the leaf of this 

 genus which enables one to 

 detect the presence of its remains 

 so long as any organic structure 

 is retained ; and at the points 

 o o are seen orifices opening 



from the interior of the cell 

 and admitting water. 

 A reference to Fig. 16 will show that the leaves of the 

 Sphagnum are borne on lateral branches. These at the 

 head of the plant form a thick and often widely ex- 

 tended tuft; but lower down the branches grow out 

 laterally from the stem, generally in tufts of four branches, 



