38 



Mycologia 



author carried on a series of experiments in the artificial pro- 

 duction of gummosis under partially controlled conditions and 

 found that gum formation, although affected to some extent by 

 variations in temperature, moisture, etc., is not dependent upon 

 or always associated with growth activity. This behavior, to- 

 gether with the fact that a pectin-dissolving enzym is always 

 found in freshly exuded gum, is held to indicate that gum forma- 

 tion is brought about by enzym activity. 



A parasite of the tree fern, Cyathea arborea, causing black 

 spots on the fronds, is described and handsomely illustrated by 

 Stevens and Dalbey in The Botanical Gazette for September, 

 1 91 9, under the name Griggsia cyathea. The genus as well as the 

 species is new and belongs in the Dothidiales. 



A long and abundantly illustrated article on the development of 

 Pluteus admirabilis and Tubaria furfuracea, by Leva B. Walker, 

 appeared in The Botanical Gazette for July, 1919. The material 

 was collected at Ithaca and in the Adirondacks, and the investiga- 

 tion conducted at Cornell during the summers of 191 6 and 191 7 

 under the direction of Professor Atkinson. 



Dr. E. P. Meinecke, of the Bureau of Forest Pathology in San 

 Francisco, visited the Garden on December 22 to consult the 

 mycological herbarium. He was especially interested in a speci- 

 men of Peridennium in the Ellis Collection, which was sent to 

 Ellis many years ago from California by Harkness. 



The influence of soil environment on root rot of tobacco 

 caused by Thielavia basicola is discussed by Johnson and Hart- 

 man in the second number of the Journal of Agricultural Re- 

 search for 1919. Saturated soils are favorable to the disease, 

 but its occurrence is determined primarily by the soil tempera- 

 ture, the optimum ranging from 17 to 23° C. Acid fertilizers 

 will not reduce infection, and fertilizers applied to heavily in- 

 fested soils are largely wasted. 



