Lecture IX 



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Structure 



surrounds the hypha for 10 or more micra but only when the wall 

 is cuticularized. Arcularius (1928) found that the host-plant sur- 

 rounds the hypha with a cellulose layer; Francke (1934) reported 

 that the haustorial hyphae are very early surrounded by cellulose ; 

 while Magnus (1900) had found the same in Neottia, and Shibata 

 & Tahara (1917) had described an analogous relation. The sheath 

 separates the living hypha from the host plasm. Kusano (1911) 

 said that the cell-wall formed papillae where hyphae passed through, 

 which were often branched or formed a "tubular sheath" that he 

 thought was lignified. Burgeff (1932) said that the wall-tubules are 

 composed of lamellate cellulose which would indicate by its structure 

 that there is a diffusion current preventing a regular layering of the 

 wall, and forming a teet-like structure. 



Hartig Net: — Hyphae, on entering the cortex, do not always 

 penetrate the cell-walls. In certain plants, particularly well seen in the 



Fig. 11. — Section of a mycorrhiza of Abies balsamea, showing Hartig net 

 which has formed about the cortical cells. 



conifers, penetrant hyphae weave about cortical cells until they form 

 a basket-weave structure in which the cortical cells are literally em- 

 bedded. Seen in section it appears as a netted structure and is called 



