198 



ELEMENTS OF STEUCTDRAL BOTANY. 



present the appearance shown at A,J?ig. 248, and if t» 3 

 magnify one of these cross-sections it will appear as at '^. 



Fig. 247. 



where there is seen an outer layer of cells standing on 

 end. The whole of both surfaces of the lamellse is 

 covered with such cells, and this special layer is the 



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



