342 Mosses. 



through which their fields alone peep forth in the strange 

 form of the letters of some eastern tongue. 



Plants of this tribe have no parts in the smallest decree 

 resembling flowers ; they have no certain mode of multiplying 

 themselves, except by the dispersion of little spores, which are 

 nothing but exceedingly minute cells, that are lodged in the 

 centre of the shields. These are very difficult to find ; you 

 may, however, make them out, if you observe the following 

 directions. Take the full grown shield of any Lichen ; with 

 a sharp knife divide it perpendicularly ; then shave off the 

 thinnest possible slice of one of the faces, and drop it into 

 water ; place it on the glass stage of a microscope, and illumi- 

 nate it from below. You will thus be able to perceive that the 

 kernel consists of a crowd of minute compact fibres, planted 

 perpendicularly upon a bed of cellular substance ; and that in 

 the midst of the fibres there is a great number of little oblong 

 bags, filled with transparent cells ; the bags are theceae, the 

 cells are spores ; and it is to the latter that the Lichen has to 

 trust for its perpetuation. 



Notwithstanding their minuteness and uninviting appearance, 

 several of them are of considerable importance to man and 

 animals. The Arctic Gyrophoras, called, by the Canadians, 

 Tripe de Roche, were the only food that the daring travellers, 

 Franklin, Richardson and Back, were for a long time able to. 

 procure, in the horrible countries they so fearlessly visited in 

 the cause of science ; Reindeer Moss (Cladonia rangiferina) is 

 the winter food of the reindeer of the Laplanders ; Iceland Moss 

 (Cetraria Islandica) furnishes a nutritious food for the invalid ; 

 and, finally, the production of Orchil, by Rocella tinctoria, is 

 an indication of the value of some species to the manufac- 

 turer, as dyes. 



