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LARCH AND SPRUCE FIR CANKER. 



The following remarks bearing on these destructive diseases 

 are the outcome of observations and experiments extending 

 over a period of sixteen years, and conducted in various parts 

 of England extending from Yorkshire to Hampshire. 



Only those experiments considered necessary to support the 

 reasons advanced as to the primary causes for the widespread 

 devastation, and the proof that such injury is due to certain 

 fungi are given ; fuller details as to methods, &c, will be 

 recorded elsewhere. 



Larch Canker. 



Dasyscypha calycina, Fuckel, Symb. Myc, p. 305 (1869). 



Syn. Peziza calycina, Schum., Enum. PL Saell., II., p. 424 

 (1803); Pcziza Willkommii, Hartig, Unters. Forstbot. Inst. 

 Munch I, p. 63, Taf. IV., p. 10 — 20 ; Corticium amorphum, 

 Willkomm ; Die mikros. Feinde des Waldes, Heft II., p. 167, 

 4 pi. (1867). 



This destructive parasite is present in greater or less quantity, 

 depending on local conditions, wherever the larch {Larix 

 europcva, D.C.) grows. In this country it also occurs on the 

 Scots fine (Pinus silvestris, L.) and on the silver fir {Abies 

 pectinata, D.C). It has been met with on young branches of 

 the mountain pine {Pinus Pnmilio, Haenke;, in Southern 

 Europe. Finally, it occurs on the balsam fir {Abies balsamea, 

 Miller), in the Lmited States. 



D. calycina is a wound-parasite, as proved by the researches 

 of Hartig (1) ; in other words, it cannot gain an entrance into 

 the tissues of a living tree except through a wound. Respecting 

 the origin and nature of these wounds more will be said later. 



Carruthers (2) has recently stated that D. calycina is not a 

 wound parasite, but that its spores can penetrate the young 

 uninjured bark of the larch. This idea is not supported by 



