Jan. r. ( <4j Cultures of Uredineae in /poj. 



31 



borne this year in part by the Indiana Experiment Station and in 

 part by a grant from the Botanical Society of America. By 

 this means I was enabled to have the services of Mr. J. Clyde 

 Marquis, an undergraduate student of the university, who made 

 part of the preliminary drop cultures and attended to the micro 

 scopical technique/and of Mr. Fred J.Seaver, a graduate of Mom 

 ingside College, Sioux City, Iowa, and a fellow in botany at 

 the University of Iowa, who mademo^^f^e^sjojwing^ 

 cultures and kept the records. ^Tfie most active period for this 

 work extends from the middle of April to the middle of June, 

 while a smaller portion of the work extends through the re- 

 maining months of the year.- 'The grant from the Botanical So- 

 ciety also permitted systematic field observations at Fair Oaks 

 in the oak barrens of northern Indiana, where many species of 

 rusts abound, for the most part unlike those occurring at Lafa- 

 yette where the chief field observations heretofore necessarily 

 have. been made. These excursions into an unworked locality 

 resulted in the discovery of the Andropogon-Comandra combina- 

 tion, the undescribed Carex-Solidago combination, and the au- 

 toecious character of the wide-spread Lespedeza rust, as well as 



minor items. 



During the present season 68 collections of material were 

 employed, and 217 drop cultures were made from them to test 

 the germinating condition of the spores. Out of these 26 col- 

 lections refused to germinate, and were consequently useless. 

 There were in all 215 sowings of spores made, representing 32 

 species of rusts, and for this purpose were required 72 species 

 of hosts temporarily grown in pots in the greenhouse. As in 

 previous years success was attained in no case except when def- 

 inite clues derived from field observations were in hand. 



In order to provide ample resources, as far as possible, so 

 that whatever suggestions are obtained even late in the season 

 can be tested without delay, a stock of teleutosporic material is 

 laid in of any species obtainable. In consequence there are al- 

 ways some species on hand in germinating condition with no 

 definite guide for their use. So far as time permits these are 

 sown upon any hosts known to bear aecidia in the region where 

 the rust abounds. The results so far have been confined wholly 

 to the negative information that the aecidia could not be produced 

 on certain hosts. The following is a record of such blind at- 

 tempts made (hiring 1903. Teleutospores were employed in 

 every case. 



1. Uromyces acuminatum Arth. on Spar Una cynosuroides 

 W'illd. from Fair' Oaks, Ind., was sown' on Hydrophyllum ap- 

 pendiculatum, with no infection. 



IVectMA PoLYGONl-AMPHlBH Pers. on Polygonum 

 emersum (Michx..) Britt. from Columbus, Ohio, and Fair Oaks, 



