BIRCH TREES IN EPPING FOREST AND ELSEWHERE. 281 



shaped perithecia with long necks make their appearance, either 

 in the same or in a separate pustule. Within each perithecium 

 are numerous asci, each containing eight uniseptate ascospores. 



Melanconis stilhostoma, being dimorphic, has been named 

 many times. In the conidial form it is Melanconium hicolor, 

 Nees., Melanconium hettdinum, Schm. et Kie., Melanconitim clevatum, 

 Cordse, Didymosporium elevatum, Lk., Didyniospoviuni betulinnm, 

 Grev. With spermatia it is N crmaspora crocea, Per., Ncemaspora 

 aurea, Friesio, Libevtella beinlina, Mazerio. With ascospores it 

 is Sphaevia stilbostoiita, Fr., Valsa sti/bostoma, Kicks., Sphaeria 

 pulchella, Currey. As fungus perfectior, nisi integer, it is 

 Melanconis stilbostoma, Tul. 



From observations made during the summer, the inference 

 is that Melanconis stilbostoma is the cause of the death of so many 

 birches, but as far as I have been able to ascertain, there is no 

 record of this fungus among plant diseases. All the authorities 

 that I have been able to consult state that it attacks dead 

 branches only, especially those of Betula alba. Tulasne, however, 

 does go so far as to mention that it is found on branches still 

 moist with sap. 



Before the supposition that Melanconis stilbostoma is the 

 cause of the disease can carry any weight, it must be demon- 

 strated that the fungus occurs also on the living branches, and 

 for that purpose the selected specimens now exhibited have been 

 chosen. The branch taken from a tree on Strawberry Hill has 

 the pustules more crowded than is usual. They had formed 

 while the cortex was still green, and before the wood showed 

 any signs of decay. There were no leaves on this tree in the 

 early summer. It was possibly first attacked last autumn, but 

 not before the leaf buds and catkins for this year had been 

 properly formed, and although these buds had not expanded, 

 they were still green. Another specimen, with the green leaves 

 still on, shows the fungus in its perfect form. One side only of 

 the branch is covered with the pustules, and the wood of that 

 side alone is brown ; it may be noticed that an offshoot from this 

 branch is still covered with green leaves. This case admits of 

 two explanations, either the wood died on one side from some 

 cause not at all evident, and became discoloured, and then the 

 fungus attacked the dead wood ; or the fungus attacked one side 



