DASYSCYPHA 



281 



willkommii (Hartig), is present in greater or less abundance, 

 depending on local conditions, elevation, etc., wherever the 

 larch {Larix europaea, D. C.) grows. It also attacks the Scots 

 pine {Pinus silvestris, L.), the silver fir {Abies pectinata, D. C), 

 Pinus laricio (Poir.), and the Japanese larch (Larix lepto- 

 iepis, Endl.). Until recently it was considered that the 

 Japanese larch grown in this country was immune to this 

 "disease ; this, however, is not so, as I have seen specimens 

 bearing this disease from England, Scotland, and Wales 

 respectively. In Southern Europe canker occurs on young 



FlG. 82. Dasyscypha calycina. 1, larch 

 branch diseased ; 2, fungus causing disease ; 

 3, ascus with spores and paraphyses. Figs. 2 

 and 3 mag. 



branches of the mountain pine {Pinus pnmilio, Haenke), and 

 the balsam fir {Abies ba/samea, Miller) suffers from this 

 disease in the United States. 



The fungus is a wound parasite, as first indicated by 

 Hartig ; this statement I have corroborated by over a hundred 

 experiments on trees of various ages, and situated in different 

 parts of the country. Fresh ascospores, that germinated 

 readily in water, were placed on the bark of young branches, 

 also in crevices of older branches, but no inoculation followed 

 in a single instance, although provision was made against 

 dessication or removal of the spores by rain. Several similar 



