THE HONEY FUNGUS 



155 



In this first 



up a trunk more quickly than transversely 

 state of rot the \vood is very Uttle affected. 



The black Hue. The second state of rot is distinguished 

 by black layers in the wood. These layers start from the 

 cambium and gradually spread inwards, remaining very thin 



Fig. 67. — Armillaria mellea. Radial longitudinal section of larch wood 

 showing the ' black line ', where it crosses a medullary ray ( x iOO). For 

 description, see text. 



all the while, so that in a transverse section of the trimk 

 they appear as Unes forming the sides of triangles with the 

 cambium as base (fig. 65). They also spread upwards 

 in the wood, forming cone-shaped sm-faces, and a section 

 thi-ough a somewhat higher part of the trimk shows them 

 as irregular circles. 



A black layer, or black fine as it appears in section, is 

 entii^ely made up of hyphae. For when the rot has reached 

 a certam stage in the wood, the hyphae become much more 

 frequently septate and bear special short branches. Both 



