60 FUNGI INJURIOUS TO PINES. 



A complete list of the parasitic fungi which injure the Pines would 

 carry us too far, and I must content myself with the following selection 

 of them. 



Some of . the most mischievous are Tram^f'* radinpenla (known 

 also as Forties annosus, Pohjpoms annosus, Heterobasidion annosuni), Tr. 

 Pini, Polypoms mollis, P. mpomnus, P. Schweinitzii, and Ayaricus 

 inelleus, 



These fungi, which are distinguished by technical characters the 

 discussion of which must be passed over here, differ considerably in their 

 mode of action and manner of inducing disease,* but they all agree 

 generally in that they eventually destroy the timber of the trees, by 

 dissolving and consuming the structural elements which compose it. 

 Now since the timber of the Pine furnishes (1) the channels up which 

 the water and nutritive materials have to pass from the roots to the 

 leaves, and (2) the supporting columns by the strength of which the 

 crown of foliage can alone be held aloft and exposed to the light and 

 air, it follows that such destruction results in disease and death to the 

 tree as a whole. 



Trametes radiciperda, now known very ' thoroughly from the recent 

 researches of Brefeld,f who also proposes to re-name it Hetero- 

 basidion annosum from the remarkable conidial forms which he 

 has discovered, attacks the living roots of Pinus sylvestris, P. Strobus arid 

 others, sending its snow-white mycelium beneath the cortex, and travel- 

 ling thence up the stem, to finally penetrate the wood by way of the 

 cambium and medullary rays. The rotting of the wood rapidly follows, 

 with symptoms so peculiar that the presence of this fungus can be 

 concluded with certainty from them. Owing to the reddish discolora- 

 tion of the timber which results, this disease has been termed the 

 " red-rot," a name Avhich involves confusion however, as several other 

 similar diseases of timber cause such discolorations. 



Tliis disease is extremely difficult to eradicate, because the mycelium 

 travels from root to root in the soil, and the spores are carried by 

 subterranean animals from one place to another; moreover, the matter 

 has become more complex since Brefeld discovered the second form of 

 conidial spores. Of course the fructifications should be destroyed by 

 burning, as also the dead and dying branches, stumps, etc. Hartig has 

 found that moats, dug so as to cut off sound trees from infected ones, 

 have been of service. 



Ayaricus inelleus, though a less pronounced parasite, is not less 

 destructive ; the details of its action on the timber are different, and its 

 mode of spreading from root to root in the soil, by means of its long, 

 purple-black, cord-like mycelial strands, called Rliizomorplia, also differs. 

 But the net results are much the same in both cases. Very tangible 

 signs of the presence of Ayarims nietteu*, in the absence of the tawny 

 yellow " toad-stools," are afforded by the copious outflow of resin from 

 the diseased roots and base of the stem of the affected trees, and by the 

 above rhizomorphs in the rotting wood and soil around. 



Most of the Polypori mentioned are decidedly wound-fungi that is to 

 say, they only attack successfully those parts of the timber which are 



'* For a more detailed account of these matters see "Timber and some of its Diseases," 

 by H. Marshall Ward, M.A., F.R.S. (Macmillan and Co.) 



t " Untersuchungen aus deni Gesammtgebiete der Mykologie,' H. VIII. 1889, p. 154. 

 8ee also R. Hartig, " /ersetzungserscheinungen des Holzss" (Berlin, 1878). 



