160 PLANTING IN UGANDA 



single specimen of the same fungus in the Upsala 

 herbarium had been previously named Fomes 

 lignosus, and hence the latter name will have to 

 be used in future. Fomes auberianus is another 

 name that was given to the same fungus. This 

 fungus is the most destructive to Hevea that the 

 planter has to contend with, and its distribution 

 is so wide within the tropics that but few planta- 

 tions are likely to escape it. The root is the part 

 attacked, and in the case of young trees, which 

 suffer most, the presence of the fungus is not sus- 

 pected, or seen, unless specially looked for, until 

 the tree has been practically killed. The presence 

 of white spawn, or mycelium, on the root is the in- 

 dication that Fomes is attacking the tree. The 

 mycelium usually takes the form of irregularly 

 branching strands, which run out into feathery 

 tips, closely attached to the bark. The mycelium 

 gradually permeates the entire substance of the 

 tap-root, softening it and making it a delicate 

 morsel for white ants, by which it is often com- 

 pletely eaten away. The ants are often looked 

 upon as the only cause of injury, but if the white 

 mycelium is present, it may be taken for granted 

 that the fungus was the primary cause. On the 



