138 OF THE LICHENS. 



any other form of plant, those are the most instructive 

 examples in which the organs of fructification are well 

 displayed. As regards the Lichens, indeed, the presence ot 

 the fruit is indispensable. _ 



Investigation into their minute structure is accomplished, 

 as in the case of the Fungi, by means of thin sections, cut 

 through both frond and receptacle. 



