Feb., 1907.] Phytnphthora and Plasmopora. 79 



favorable conditions. It is strongly, positively phototactic, 

 not only to white light, but to red, green, violet, orange, blue and 

 yellow, showing a probable preference for red. 



Ohio Wesleyan University, 



Delaware, Ohio, November, '06. 



Literature Cited. 



Forbes, vS. A., '76 — List of Illinois Crustacea. Bull. 111. State 

 Lab. N. H., No. 1, 5. 



Hay, O. P., '82 — Notes on Fresh-water Crustacea. Amer. Nat- 

 uralist. XVI-(144) 1882. 



Smith, Sidney I., '72 — Report of U. S. Fish Com. Fresh-water 

 Fisheries of the U. S. Report of 1S72-73-A, Synopsis of 

 the Higher Fresh-water Crustacea of the Northern U. S., 

 pp. 041-42. 



Stimpson, William, 71, Ann. N. Y. Lyceum N. H., x loO (Not 



seen). 



ON THE OCCURRENCE OF PHYTOPHTHORA INFESTANS 

 MONT. AND PLASMOPORA CUBENSIS (B. &C.) HUMPH. 



IN OHIO.* 



A. D. Selby. 



The first named fungus, parasitic upon potato, Phytophihora 

 infestans Mont., is a species of large economic importance, whose 

 periodic epidemic outbreaks have become historic and have had 

 far reaching economic and political effects. Most of you will 

 recall the statements, that the potato rot resulting from this 

 fungus, occurred in a virulent form in Eastern North America 

 in 1842 and again in 1845 — also in 1874. In 184.5, and at later 

 dates the disease spread to Great Britain, Ireland, Belgium and 

 parts of Germany and France. In one earlier year, 1845, the 

 greatest injury was done in Nova Scotia, New Brunswick and 

 in Ireland. 



This restatement of old facts is made to ask you to bear in 

 mind the climate of the areas of greatest disease. 



Doubtless most have heard of potato late blight and rot from 

 this fungus and may be surprised to learn that it is of such rare 

 occurrence in our state that not a single Ohio specimen of 

 PhytopJithora infestans is to be found in any of the herbaria of 

 the country, save only a few collected at the Ohio Experiment 

 Station within the last three years. However, I know that 

 specimens were taken by the late Dr. E. W. Claypole, near Ak- 

 ron, O., in the early 8()'s, since I saw him once exhibit such ma- 

 terial. This material was unfortunately destroyed in the fire 



* Read at the meeting of the Ohio Academy of Sci. 



