LARCH AND SPRUCE FIR CANKER. 25 



III. Larch and Spruce Fir Canker.^ By George Massee, F.L.S. 



The following remarks bearing on these destructive diseases 

 arfe 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 suppoi't 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, etc., will be 

 recorded elsewhere. 



Larch Canker. 



Das]jscijpha cahjcina, Fuckel, Symb. Myc. , p. 30.5 (1869). 



Syn. Peziza cabjcma, Sclium., Enum. PI. Saell., ii. p. 424 (1803); 



Peziza Willkomii, Hartig, Unters. Forstbot. Inst. Miinch, i. 



p. 63, Taf. IV. pp. 10-20 ; Corticium amorpliiom, 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 

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

 Scots pine (Pinus sylvestris, L.) and on the silver fir [Abies 

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

 mountain pine {Pinus pumilio, Haenke) in Southern Europe. 

 Finally, it occurs on the balsam fir {Abies balsamea, Miller) in 

 the United 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 any 

 account of actual experiments, and is quite contrary to my own 

 experience. One hundred and four inoculations on young un- 

 wounded branches of larch, in some instances seedlings, in others 

 old trees, extending over several years, made at difi'erent seasons 

 and under varied conditions, by using fresh ascospores which 



^ Reprinted from the Journal of the Board of Agriculture, by permission of 

 the Controller of His Majesty's Stationery Office. 



