198 



ELEMENTS OF STRUCTURAL ROTANY. 



present the appearance shown at A, Fig. 248, and if we 

 magnify one of these cross sections it will appear as at B, 



Fig. 247. 



where there is seen an outer layer of cells standing on 

 end. The whole of hoth surfaces of the lamellee is 

 covered with such cells, and this special layer is the 



Fig. '247. Various stages in the development of a Mushroom. (Sachs.) 



