62 DISEASES OF CULTIVATED PLANTS 



fungus may frequently be seen growing up heather stems, it 

 also spreads for a considerable distance on the ground. 

 The general colour is brown, texture soft and fibrous, almost 

 shaggy on the upper surface, wrinkled or papillose below, 

 margin shaggy or torn. 



Fairy-rings. Several different kinds of fungi form the 

 well-known fairy-rings, which often greatly disfigure and 

 injure lawns, bowling-greens, etc. Marasmius oreades (Fr.), 



: 



FIG. 9. Tuber of potato pierced by the underground creep- 

 ing stolons of couch-grass ( Triticum repens). Nat. size. 



is a well-known offender in this respect, but species of 

 Tricholoma and Lycoperdon also participate. When a fairy- 

 ring once commences, it increases in diameter year by year, 

 the mycelium constantly growing outwards into new ground, 

 hence each season the crop of toad-stools is just outside the 

 zone of ground occupied by the crop of the previous season. 

 The mycelium obtains food partly from humus, and partly 

 from the living roots of the grass. 



Soak the ground thoroughly with a solution of sulphate of 

 iron one pound to a gallon and a half of water ; for later 

 applications, at intervals of a fortnight, use the solution at 

 half the above strength. About three applications should 

 suffice. It is important that the solution be applied 

 when the soil is wet. If rain has not fallen the ground 

 should be previously well watered. Lifting the turf with a 

 fork enables the solution to penetrate the soil more readily. 



