CLASSIFICATION UK I'AKASITKS AND SAl'KuTH VI I -. 5 



As further examples of fun-i, capable, as parasites,, of killing 

 living cells, but which pass through more or less of their life 

 as saprophytes, may be taken species whose mycelium inhabits 

 the wood of trees and shrubs. Amongst these are numerous' 

 Polyporeae ) which find admission only by wounds in tin- wood. 

 At first these destroy and derive nourishment from tin- substance 

 of dead parts of the wood, but later they begin to attack the 

 parenchyma of the living wood, and extending nut wards kill, 

 as they go, cambium, bast, and rind, till they reach the exterior, 

 and there develop sporophores. As examples we may take 

 those species investigated by II. Hartig of Munich, ///. P"l//- 

 porus fom&ntarius, P. //////'" ////*, P. If/-f\</ii, P. *////////// 

 Stereum /> //-///' /////, Tru-unff* />i/n. 1 



The heart-wood is a part of the tree generally avoided by 

 insects, which would in very short time destroy the sap-wood 

 with its rich starch-content, <.//. Anitlii<c' in oak. Again, the 

 heart-wood resists the intluence of certain saprophytic fungi 

 much longer than the sap-wood, hence it is preferred as the 

 timber used for railway sleepers. Although in these cases we 

 might describe the heart-wood as possessing antiseptic properties 

 yet this would scarcely be accurate, since it is just this very 

 heart- wood which is always first attacked by the wound-parasite- 

 of trees, and uives them a hold on the tree as parasites. See 

 also ( 'liaji. V. 



Since these dangerous tree-fungi can live wholly as sapro- 

 phytes in the heart-wood, and in the sap-wood partly as such. 

 partly as parasites, they are also able to vegetate further, and 

 to reproduce themselves on felled stems, especially when the 

 necessary moisture is provided. Thus, for example, Aym-im* 

 m////n,s//x, a wound-parasite of the silver tir, produces its yellow 

 sporophores on felled stems and split wood during the whole 

 summer in moist parts of the forest, while in a cellar or other 

 moist chandier the development of >porophorcs may continue over 

 a year. In fact, I have found that a billet of beech-wood, after 

 beiii'j; jilaced under a glass and allowed to lie completely dry, 

 on auain being soaked from time to time, continued to produce 

 a crop of toadstools annually for live years. 



Some wound-parasites occur occasionally as typical sa]>i"- 

 phvtes on dead Wood. Thus /V///"//'//.s annOSUS, perhaj^ better 



'I:, ll.uti.', ZertetTungtcrschrinungen det II- -, i>7-v .m.l i.tlu-r <> 



