90 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Tree Root Rot. (Agaricus melleus, Vahl.) 



This fungus belongs to the group commonly known as 

 "toadstools," and grows in dense clusters at the roots of trees 

 and around stumps. Every part except the gills is dingy yellow 

 or honey colour ; the cap is two to three inches broad, and 

 the stem four to six inches long, with a torn frill or ring 

 placed about an inch from the top. The gills are white. This 

 fungus" grows readily on decaying wood, and in some cases 



Fig. G. — Tree Root Rot (Agaricus melleus). One quarter natural size. 



appears to grow in the soil ; but in such cases, if carefully 

 examined, it will be found to spring from buried wood, roots, &c. 

 The mycelium or spawn forms thin, blackish, cord-like strands, 

 which run a few inches under the soil for a distance of many 

 yards from the parent plant. If one of these strands happens 

 to come in contact with a young root-branch of a growing 

 tree, the mycelium soon enters the tissues of the root, where 

 it spreads rapidly, both in the root and in the soil, attacking 

 every rootlet with which it comes in contact, until eventually 

 every portion of the root becomes covered with a white, cottony 



