Mosses and Lichens 



first noticeable in a young spore-case as a groove. This groove 

 is due to one zone of cells growing less rapidly than the zones of 

 cells on either side. The breaking along the groove is due to 

 the thinner walls of the groove cells. One zone of thicker- 

 walled cells forms a rim to the spore-case and the other zone of 

 thicker-walled cells forms the rim of the lid. 



6 r o o v t 



..oj 

 ... Spore- sac, 



.C.al 



uxxli. 



Vertical section of a young sporogonium. 



The character of the leaves and the manner of branching, 

 both of which are visible to the naked eye, enable one to separate 

 the species with some accuracy into eight groups, which are 

 helpful to a beginner, in that they gave him some definite points 

 of difference to look for in a genus of which to the novice all 

 species appear alike. 



SYNOPSIS OF GENUS SPHAGNUM 



i. Acuta. With branch-leaves erect and stem leaves large. 

 Examples: Sphagnum acutifolium and Sphagnum rubellum. (See 

 diagram on page I2j$.) 



122 



