CULTURES OF UREDINEAE IN 1909' 



J. C. Arthur 



The year 1909 marks the beginning of the second decade of 

 culture work by the writer. The present report is preceded by 

 nine other similar reports- covering work done between 1899 and 

 1908 inclusive, each issued annually except the second one, which 

 covered two years. The following account of the work for the 

 year 1909 is divided into a general introductory part, a list of 

 negative results, in which the sowing of the spores did not bring 

 hoped-for infection but the record seemed worth preserving for 

 use in directing future work, and a list of positive results, in 

 which the sowing of spores caused an infection that gave rise to 

 characteristic fruiting bodies. The successful sowings largely 

 belonged to species previously cultivated, and are recorded to ver- 

 ify or amplify existing knowledge. A small number of success- 

 ful sowings were made with species never before cultivated, and 

 whose alternate forms had never before been associated. 



The work of the year was carried on under adverse and trying 

 conditions, A new building for the experiment station was be- 

 gun in the previous autumn, and was located upon the ground 

 where for many years a great variety of plants has been grown, 

 especially brought together for this work. It was in effect a 

 small botanical garden filled with plants from all over the con- 

 tinent known to serve as hosts for different species of rusts, and 

 from which plants were in large part drawn for the cultures. As 

 many plants as possible were removed to another plot of ground 

 some distance away, but many species were wholly lost. The 

 seedlings of self-sown annuals were especially missed in pro- 

 viding potted plants for the spring's work. The heavy infec- 

 tional work had only begun in April when it became necessary to 

 abandon the greenhouses where the work was in progress, so they 



^ Read before the Botanical Society of America at the Boston meeting, 

 December 29, 1909. 



-See Bot. Gaz. 29: 2(i?,-2T(i, 35: 10-23; Jour. Myc. 8: 51-56, 10: 8-21, 

 11: 50-67, 12: 11-27, 13: 189-205, 14: 7-26; and Mycol. i: 225-256. 



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