204 PLANT DISEASES 



thus preventing, to a great extent, the spreading of the 

 underground rhizomorphs to adjoining trees. 



Armillaria mellea is edible ; hence if the fungus appears 

 it may be eaten, and, although rather devoid of flavour, if 

 properly cooked forms by no means a despisable dish. 

 However, apart from this, the fungus should always be 

 collected and burned when it appears in the neighbourhood 

 of fruit or ornamental trees, as, if the spores are allowed to 

 disperse, they germinate and produce the creeping rhizo- 

 morphs. A fertile source of infection consists in the careless 

 manner in which the base of the trunk or partly exposed 

 roots of trees are often wounded by the spade, cart-wheels, 

 and perhaps more especially by grass-cutting machines ; 

 such wounds forming a starting-point for the attack of 

 various kinds of injurious parasitic fungi. All such wounds 

 should be at once protected by painting over the broken 

 surface with tar, which prevents decay and also the germina- 

 tion of the spores of fungi on the wound. 



Hartig, Die Zersetzung. des Holzes, p. 59, tab. xi., figs. i.-v. 

 Hartig, The Diseases of Trees (Engl. ed.), p. 207, with figs. 

 Prillieux, Malad. des Plantes Agric., vol. i. p. 377. 

 Marshall Ward, Timber and some of its Diseases, p. 155, 

 figs. 



BEECH AGARIC 



(Armillaria mucida, Schrad.) 



This fungus is a wound-parasite on the beech. At High 

 Beech, Epping Forest, where this fungus is abundant on 

 decaying beeches, a healthy branch of a beech having been 

 broken off, the wound was inoculated with the spores of 



