March 1905] Cultures of Uredineae in 1904 . 
53 
Teleutosporic material on Populus tremuloides 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 11 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 Heiianthus laetidorus, 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 
9 Jour. Mycol. 10:13. 1904. 
10 Bot. Gaz. 29:271. 1900. 
11 Bot. Gaz. 35:17. 1903. 
