i8o PLANT DISEASES 



PREVENTIVE MEANS. When a tree once produces 

 sporophores of the fungus, cure is hopeless, and it is not 

 even worth while taking the trouble to remove the sporo- 

 phores, as another crop would soon be produced by the 

 vigorous mycelium present in the tissues. The best thing 

 to do is to fell diseased trees, and thus save the bulk of 

 the timber, for if allowed to stand, the great bulk of the 

 wood is rendered useless ; besides which, the sporophores 

 liberate spores that in turn inoculate other trees. 



Hartig, Wichtige Krankh. der Waldbaume, p. 43 ; Zer- 

 setzungs. des Holzes, p. 32, pi. v. and viii. 



Hartig and Somerville, Diseases of Trees (Engl. ed.), 

 p. 191, figs. 



Tubeuf and Smith, Diseases of Plants (Engl. ed.), p. 453, 

 figs. 



Trametes suaveoleus, Fr., occurs as a parasite on willows. 

 Bracket-shaped, pileus whitish, downy ; flesh white, rather 

 soft and corky; pores white, then brownish. Smell, 

 especially when vigorously growing, fragrant, resembling 

 aniseed. 



PORIA WOOD ROT 



(Poria vapor aria, Fries.) 



One of the commonest and most widely distributed of 

 British fungi, and as a saprophyte occurring on almost 

 every fallen branch to be found lying on the ground. 

 Every part of the fungus is inseparably attached to the 

 matrix, forming a thin crust, white at first, becoming dingy 

 with age. The entire surface except the extreme margin 



