﻿CULTURES OF UREDINEAE IN 1902.^ 



J, C Arthur, 



The present article 



by 



the author upon the cultures of plant rusts. The first one ^ 

 covered the year 1899, the second^ combined the years 1900 

 and 1 90 1, and the third covers the year 1902. Like the 

 preceding ones, the present report is devoted largely to the 

 heteroecious grass and sedge rusts. The methods employed 

 have already been described in connection with the previous 

 reports. 



The work was much more extended during the present sea- 

 son than had been possible in preceding years through the 

 interest taken in it by the authorities of Purdue University, 

 who generously defrayed the expense of additional assistance 

 during the months of May and June, when the largest part of 

 the work must be done. In this way it became possible to have 

 the help for a time of Mr. Oliver P, Terry, an undergraduate 

 of the university, and an unusually skilful manipulator. But 

 the larger part of the testing with drop cultures and of the 

 application of the spores to the plants throughout the whole of 

 the busiest period was undertaken by Miss Julia Titus Emerson, 

 of New York City, coming from the New York Botanical Gar- 

 den, who showed great earnestness and rare judgment in carry- 

 ing on the work. 



During the present season 123 collections of material were 

 employed, and 314 drop cultures were made from them to 

 , test the germinating condition of the spores. Out of these 23 

 collections refused to germinate, and were consequently useless. 

 There were in all 327 plant cultures attempted, representing 43 

 species of rusts, and employing 102 species of hosts tempo- 



'Read before the Botanical Society of America, Washington, Jan. i, 19^3' 

 ^BoT. Gaz. 29: 268-276. April 1900. 

 3jour. Mycology 8 : 5I~S6. June 1902. 



10 [JANUARY 



