Mosses and Lichens 



withstand the fierce heat of the sun, they have various interesting 

 contrivances for folding their leaves so as to retain what moisture 

 they have absorbed, and they have methods of trans- 

 ferring their delicate leaf-green from one part of the 

 plant, too much exposed to the sun, to a part less 

 exposed, or of surrounding the leaf-green-bearing cells 



Stem with 



Portion of leaves, 



leaf to show 

 marginal cells 

 different from 

 body cells. 



Mnium punctatum. 



Mnium cuspidatum. 

 Stem with leaves. 



Pogonatitm 

 Alpinum. Apex 

 prolonged into 

 an awn. Margin 

 serrate- Surface 

 covered with 

 delicate cells. 



in a wall of large colourless cells. This arrange- 

 ment accounts for the fact that some mosses, as 

 the peat-mosses (Sphagnum, Plate XI), white- 

 mosses (Leucobryum, Colour Plate IV), and others 

 appear light gray when dry and green when wet. 

 The luminous moss has given up- the struggle 

 for a place in the outer world 

 and has retreated to caves where 

 but a few rays of light enter. It 

 has adapted itself to the semi- 

 darkness by 

 devising a 

 method where- 

 by it can con- 

 verge the sev- 

 eral feeble rays 

 which fall upon 

 it so that they 

 form one beam 



Cell. 



Sphagnum cymbifolium. Surface view of leaf- 



Bryum argenteum. 

 Leal with open cell - 

 structure. 



