Fig. 149. Mycorhiza : to the left is the tip of a rootlet of beech enmeshed by the 

 fungus; A, diagram of longitudinal section of an orchid root, showing the cells 

 of the cortex (p) filled with hyphoe; B, part of longitudinal section of orchid root 

 much enlarged, showing epidermis (e), outermost cells of the cortex (p) filled with 

 hyphal threads, which are sending branches into the adjacent cortical cells (a, i). 

 —After Frank. 



V-4. 



Fro. 150. Mycorhiza: A, rootlets of white poplar forming mycorrbiza; B, enlarged 

 section of single rootlets, showing the hyphae penetrating the cells.— After 

 Kerner. 



