154 PLANTING IN UGANDA 



stronger solution than others, experience will be 

 the great guide in such matters. 



So far, we have been dealing with those fungi 

 which attack the foliage and above-ground parts of 

 plants by means of spores. We now come to con- 

 sider a second group, which have a different and 

 far more damaging method of attack. To this 

 second group belong those fungi whose spawn or 

 mycelium live in the humus and travel long 

 distances in search of new plant roots, when the 

 tree they have already attacked is dying from their 

 ravages, and no longer supplies the required 

 amount of food. The fungus produces its fruit 

 on some above-ground portion of the dying tree, so 

 that the spores may be carried by various agencies 

 and infect other trees. 



Although the fungi belonging to this group can 

 reproduce themselves by spores, yet the most 

 serious injury they do is by means of their myce- 

 lium, which is usually in the form of white strands 

 spreading in the ground in every direction a few 

 inches below the surface. To this group belong 

 the large bracket-like fungi, the large agarics, or 

 toadstools, as well as many minute or microscopic 

 kinds. Stumps left in the ground, as is well 



