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(Reprinted from the Journal of Mycology, Vol. 8, June 1902.) 



CULTURES OF UREDINEAE IN 1900 AND 1901 



BY J. C. ARTHUR. 



The first especially important cultures of plant rusts made by 

 the writer were conducted in 1899, and the results published in 

 the Botanical Gazette for April 1900 (29:268-276). During the 

 two following years only a small number of cultures were made, 

 and for a number of reasons the results have not been put into 

 type until now. This article is, therefore, the second of the series. 



The method pursued in most cases in making the cultures 

 has been stated in the preceding article. It was, in brief, to re- 

 move spores with a knife from the host, and place them on a 

 dampened plant which it is desired to infect. The plants are 

 grown in pots. After the spores are sown the whole plant is 

 covered with a bell jar and kept shaded for a day, or sometimes 

 two days. The plants are then uncovered and placed on a 

 greenhouse bench, where they remain until the period of ob- 

 servation is ended. 



In 1900 the only cultures made that require mention were 

 with Euphorbia rust. The results supplement and confirm those 

 made in 1899 (Bot. Gaz. 29:270-271). It was again found that 

 spores from Euphorbia nutans would grow upon the same species, 

 but not upon E. maculata. It seems quite probable that this rust, 

 Uromyces euphorbiae C. & P. possesses specialized forms. The 

 record is as follows : 



