INJURIES INDUCED BY PLANTS 207 



taken to do nothing that will cause the formation of wounds 

 in trees, of which more will be said in the section on wounds ; 

 and, secondly, where wounds are intentionally produced on trees, 

 as in pruning, the necessary prophylactic measures must be at 

 once put in force, and in particular an antiseptic dressing in 

 the form of a covering of tar should be provided. 



At the same time woods should be kept tidy and free from 

 decaying wood, which may bear the sporophores of parasites, 

 but this must not be taken to mean that all old oaks that 

 are already decayed are to be felled without regard to other 

 considerations. For the sake of effect the forester should allow 

 old trees and picturesque bits of timber to stand where deemed 

 desirable in the neighbourhood of frequented paths, even 

 although the benefits of so doing may not be at once manifest 

 in the shape of hard cash. 



AGARICUS MELLEUS. 1 * THE HONEY AGARIC 



This fungus belongs to the most widely distributed and 

 destructive of parasites. It lives parasitically on all European 

 conifers, besides destroying those that have been introduced 

 from Japan, America, &c., and I have even recognized it in the 

 fossil wood of Cupressinoxylon. Amongst dicotyledonous trees it 

 appears to occur as a parasite on Primus avium and P. domestica, 

 while as a saprophyte it is to be met with everywhere, not only 

 on the dead roots and stools of all dicotyledonous and coniferous 

 trees, but also on the structural timber of bridges, conduits, mines, 

 &c. It has frequently been asserted that it also occurs as a 

 parasite of the vine, but I have had no opportunity to convince 

 myself of the correctness of this view. Those rhizomorphs 

 whose occurrence I have hitherto observed on the vine belonged 

 to Dematophora necatrix. 



The disease often manifests itself on plants only three to five 

 years old, though it also destroys spruces, pines, &c., a century 

 old. One recognizes it by removing the bark at the collar 



1 R. Hartig, Wichtige Krankheiten der Waldbaume, 1874, pp. 12 et seg., 

 Tables I. and II. R. Hartig, Zersetzungserscheinungen^ pp. 59 et seq., Table 

 XL, Figs. 1-5. 



* [This is one of the commonest of British fungi, and its rhizomorphs and 

 sporophores are well known. ED.] 



