The Parasitism of Nectria cinnabarina. J. Line. 23 
It is almost impossible to reconcile these results with those of 
Wehmer(z) who from observations on the lime and hornbeam 
in 1894 concluded that the fungus became parasitic, but that it 
was strictly confined to the cortical regions, never entering the 
woody tissues. He considered that Mayr was completely mis- 
taken in his observations or that he was working with another 
fungus. 
Durand(3) in 1897 described the appearance of the fungus on 
red currant in the U.S.A., his descriptions of the disease tallying 
exactly with the symptoms observed during 1919 and 1920 in 
this country. He considered that it was acting as a parasite, 
but although he performed infection experiments with pure 
cultures of the fungus, he does not record any of his results. 
It is well known that coral spot often occurs on dead branches 
of otherwise healthy red and black currant bushes in this 
country. It was pointed out to the writer in 1919, by Mr F. T. 
Brooks, that it had never been shown how much of the die-back 
observed was due to the primary action of the Nectria, and 
how much to the action of one or other of the fungi often 
associated with it. 
An investigation was therefore started in order to settle if 
possible 
(I) to what extent the fungus may be regarded as a parasite, 
particularly on the red currant; 
(2) its normal method of infection and method of growth in 
the host tissues; 
(3) whether any differences in power of infection could be 
detected between different strains of the fungus. 
FIELD OBSERVATIONS. 
A number of orchards were kept under fairly close observa- 
tion during the years 1919 to 1921, and a very large number of 
the bushes were found bearing the stromata of Nectria on one 
or more of their branches. Other commonly occurring fungi 
were Collybia velutipes and Fomes Ribis. A few bushes were 
found bearing Stereum purpureum and Botrytis. No experi- 
mental work was done with these fungi, but a short summary 
of observations made on them will be found elsewhere. 
During this preliminary examination of the bushes, single 
branches on apparently healthy bushes were often found showing 
signs of wilting of the leaves. In some cases this was observed 
just after the leaves had expanded, but others did not become 
wilted until about flowering time. Later on branches bearing 
nearly ripe and quite normal fruit were found suddenly to 
become wilted (Figs. r and 2). Such branches when left on the 
bush were observed to lose all their leaves during the summer, 
