116 



Mycologia 



spores about 14X5/^ and also without constrictions. These are 

 nearer the figures given in the North American Flora. 



Although this fungus, under the name of Nectria ditissima Tul., 

 is presumably the cause of the " European apple-tree canker " in 

 North America,^' * we have found no reference to it as a 

 pathogenic organism on forest trees in North America, if we 

 except the paper by Pollock,^ in which he speaks of a fungus 

 resembling A^. coccinea, associated with a canker of the yellow 

 birch (Betida lutea Michx. f.) in Michigan. Many points in his 

 description coincide with the facts set forth above. In particular, 

 his spores agree with ours in that they are wider than the figures 

 cited in the type descriptions. Perhaps the variation in form is 

 due to the influence of the host. Cook^*^ has reported a Nectria 

 parasitic on the Norway maple, but was unable to determine the 

 species with certainty. In correspondence with the writer he has 

 stated that it was probably Nectria cinnabarina. 



As already intimated, Nectria ditissima Tul. as well as N. 

 coccinea Fr. are considered synonyms of Creonectria coccinea 

 (Pers.) by Seaver in the treatment in North American Flora. 

 Yet there still seems to be some confusion as to just what is 

 meant by Nectria ditissima Tul. Seaver^^ says : " So far as we 

 can see the species (Creonectria coccinea) scarcely differs from 

 Nectria ditissima Tul. If the two species are distinct, the char- 

 acters are so poorly understood that they have been badly con- 

 fused." We have for a long time been accustomed to regarding 

 Nectria ditissima Tul. as the causal fungus of the canker of de- 

 ciduous trees in Europe. And yet, according to Shear/^ Euro- 



6 Wilson, G. W. Notes on three limb diseases of apple. N. C. Agr. Expt. 

 Sta. Rept. 35: 49. 1913- 



7 Duggar, B. M. Fungous diseases of plants. Pp. 242-243. 1909. 



8 Morse, W. J. Spraying experiments and apple diseases in 1913- Me. 

 Agr. Expt. Sta. Bui. 223: pp. 23-24. 1913. 



9 Pollock, J. B. A canker of the yellow birch and a Nectria associated 

 with it. Mich. Acad, of Sci. Rept. 7: 55-56. 1905- 



10 Cook, Mel. T. A Nectria parasitic on the Norway maple. Phytopath. 7: 

 313-314. 1917- 



11 Seaver, F. J. The Hypocreales on North America. Mycologia i: 188- 

 189. 1909. 



12 Shear, C. L. Some observations on phytopathological problems in 

 Europe and America. Phytopath. 3: 80 ff. 1913- 



