MYCELIUM 



mischief. The hyphae forming this vegetative system may be 

 immersed, and probably are so in the majority of instances, 

 but they may also form a stratum on the surface, and adhere 

 by haustoria or suckers, which are short branches designated 

 for the purpose, or for that combined with the absorption of 

 nutriment. The hyphae when young have colourless cell walls, 

 but as they grow older the walls thicken and acquire colour, 

 sometimes with an appearance of stratification. In some 

 cases cross branches anastomose, or form clamp 

 connections (Fig. 1). Gardeners are well aware 

 that immense masses of white mycelium are some- 

 times met with in turning over the soil. These 

 mark the site of an old tree when part of the 

 stump or dead roots have been left to rot in 

 the ground. Numerous instances are on record 

 in which trees or shrubs, when planted in soil 

 overrun in this manner with mycelium, have 

 been killed, and when taken up the roots found F . i , , 

 to be enveloped in mycelium. Practical men connections. 

 are quite aware that this has occurred over After DeBar y- 

 and over again, and yet some theorists contend that it is 

 not possible, because the mycelium is a saprophyte, that 

 is to say, flourishes upon dead organic matter, and not 

 upon living tissues. Observation has nevertheless decided 

 that in some instances a saprophyte may become parasitical, 

 and a parasite may acquire the habits of a saprophyte. The 

 instances may not be common, but are not impossible. Against 

 theory we are prepared to contend, from experience, that we 

 have seen plants killed, after planting in a soil overrun with 

 mycelium, from no other assignable cause, and afterwards dug 

 up with the roots enveloped in mycelium. 



It has been stated above that mycelium is usually colour- 

 less, and it is generally so with the Basidiomycetes, but there 

 may be exceptions, as in Corticium sanguineum, with its 

 mycelium of a blood red, in Maphomyces Zeveillei, of a yellowish 

 green, in Ghlorosplenium aeruginosum, of a verdigris green, and 

 in many of the Dematiaei, of a dark brown, or almost black. 

 And so also it may differ considerably in quantity, from a few 

 scattered threads to a dense matted felt. Even in this country 



