114 



Mycologia 



In the New York region, no tract where Betula lenta formed 

 a fair per cent, of the stand was free from the disease. In 

 the fall of 19 1 8 a forest at Milford, Conn., was visited, where 

 about 50 per cent, of the stand was sweet birch, and at least 90 

 per cent, of the trees were affected. Dr. G. P. CHnton states that 

 he has noticed the trouble for many years, and showed the writer 

 specimens collected on Betula lenta near New Haven in 1906. 

 The writer collected specimens of the causal fungus, Creonectria 

 cocci)iea (Pers.) Seaver (Neetria coccinea Fr.) from trees in 

 Van Cortlandt Park, Mt. St. Vincent, Staten Island, and the 

 terminal moraine north of Hollis, L. L, but the disease was seen 

 in many other localities. 



The symptoms are typical lipped cankers, which if old are open, 

 but in a younger stage may be still covered over with dead bark 

 and then only appear as sunken spots with the bark cracked at 

 the margins. Usually several cankers appear on a single tree, 

 distributed at irregular intervals along the trunk and branches. 

 Branches even as small as ^ inch in diameter may have the 

 cankers, and such lesions, from their characteristic, irregular, 

 nodular appearance, may be recognized readily from a distance. 

 The fungus advances in the living bark during the season of inac- 

 tivity of the host. Thus, during October, November and early 

 December, and again in early spring, the new bark recently killed 

 by the fungus can easily be observed by cutting in at the margins 

 of the canker. The freshly diseased cortex has a sodden consis- 

 tency and a dark reddish hue, contrasting sharply with the yellow 

 color of the healthy inner bark, while at the boundary between 

 the two a dark red line appears. With the new season's growth 

 of the cambium, the inroads of the fungus are temporarily 

 checked, to be resumed again in the fall. In this way the succes- 

 sively receding layers of wood about the canker are formed. The 

 disease thus progresses slowly, and in many cases may be present 

 in the tree for a long period, the increase in circumference of the 

 tree more or less compensating for the loss of cortex through the 

 fungous attack. One large tree, about 2^ feet in diameter, 

 breast high, near Whitestone, L. I., was seen which had been 

 affected apparently for many years, one of the cankers, near the 



