March 1905] Cultures of Uredineae in 1004 



47*r 



Teleutosporic material on Populus trcmuloides Michx. was 

 sent from Racine, Wis., by Dr. J. J. Davis, and was sown on Larix 

 decidua, May 25. Abundance of well developed spermogonia 

 appeared on June 5, followed by strongly developed aecidia on 

 June 10. This culture is specially significant in showing that the 

 poplar rust of North America is probably all of one species, as 

 assumed in last year's report of cultures. 9 



2. Phragmidium speciosum Fr. has twice before been the 

 subject of cultures, being grown in 1899 10 on a tea rose from the 

 garden, and in 1902 u on Rosa humilis. The teleutosporic mate- 

 rial used this season was obtained by the writer at Spirit Lake, 

 Iowa, on Rosa Arkansana. It was sown on R. Arkansana Port., 

 R. Carolina L., R. humilis Marsh., and R. nitida Willd., with 

 abundant success in each case. It was sown twice on R. lucida 

 Ehrh. without success, although the host was in fine growing con- 

 dition. The dates were as follows : 



May 7, Teleutospores sown on R. Arkansana; May 14, spermogonia ; May 



20, aecidia. 

 May 7, Teleutospores sown on R. Carolina; May 14, spermogonia ; May 



18, aecidia. 

 May 17, Teleutospores sown on R. humilis; May 23, spermogonia; May 



30, aecidia. 

 May 17, Teleutospores sown on R. lucida; no infection. 

 June 1, Teleutospores sown on R. lucida; no infection. 

 June 1, Teleutospores sown on R. nitida; June 8, spermogonia ; June 15, 



aecidia. 



Whether the failure to infect R. lucida was due to the greater 

 mechanical resistence of the firm leaves, or to a physiological dif- 

 ference in the host can not be stated, but I am inclined to favor the 

 former explanation. 



3. Puccinia Helianthi Schw. Three collections of sun- 

 flower-rust were used for cultures this season. A collection was 

 obtained from Spirit Lake, Iowa, on Helianthus laetiHorus, one 

 from Fair Oaks, in northern Indiana, on H. mollis, and one from 

 Lafayette, Ind., on H. grosse-serratus, all by the writer. Another 

 collection was used, but the host could not be determined with cer- 

 tainty, and the results are discarded. Three collections seemed to 

 be in perfect condition, but could not be made to germinate. Forty 

 sowings were made from the three collections used, and as a large 

 space would be required to report the full data, the results will be 

 given in tabular form. In this table decided and complete results 

 are shown by an exclamation point, infection which was meager, 

 grew slowly and gave no aecidia or very few, is shown by a semi- 

 colon, a sowing which gave no infection is indicated by a single 

 period, and where no sowings were made a dash is used. Fifteen 



'Jour. Mycol. 10:13. 1904. 

 10 Bot. Gaz. 29:271. 1900. 

 u Bot. Gaz. 35:17. 1903. 



