Arthur: Cultures of Uredineae in 1909 231 



leaves soon died. Still another sowing was made June 14 on 

 Sorb us amcricana, producing numerous pycnia June 26, but the 

 plant gradually died.^^ 



21. Gymnosporangium floriforme Thax., on Junipcrus vir- 

 giniana L., collected at Aiken, S. C, by Mr. F. D. Kern and the 

 writer, was sown March 26 on Mains Mains with no infection, 

 and at the same time on Crataegus coccinca, giving pycnia in 

 abundance April 12. The after development, however, was very 

 slow, and by the middle of July aecia had only begun to show, 

 and grew so very slowly that they did not reach full size, although 

 observations were continued till November 11. Another sowing 

 from the same material was made May 15 on the same host, re- 

 sulting in a few pycnia, but no aecia. In both cases the infected 

 leaves matured too rapidly for the very slow growing aecia, and 

 besides, the host used is not a species on which natural infection 

 is likely to occur. 



Previous cultures have been made by Dr. R. Thaxter at Cam- 

 bridge, Mass., and Prof. F. S. Earle at Auburn, Ala'. Only a 

 slight notice of these cultures has been published. A description 

 and historical account of the species was recently published by 

 Mr. F. D. Kern.^^ The telial form of the species is very similar 

 in appearance to that of the common Gym. Juniperi-vir ginianae . 



22. Gymnosporangium exterum Arth. & Kern, on Junipcrus 

 virginiana L., a living plant a little over six inches high, which 

 has been growing in the greenhouse since being brought from 

 Mammoth Cave, Ky., by Mr. F. D. Kern and the writer a year 

 ago, was sown May 14 on Porteranthus stipulatus {Gillenia stip- 

 nlacca), and gave rise to an abundance of pycnia May 22. On 

 June 14 the first aecia appeared, which were mature June 26. 

 The work duplicates and confirms that of last year.-^-^ 



23. Calyptospora columnaris (A. & S.) Kiihn, on Vaccinium 

 peniisylvanicuui Lam., collected at Pictou, Nova Scotia, by Prof. 

 W. P. Fraser, was sown June 16 by suspending the moistened 

 stems bearing the rust over potted plants of Abies Fraseri. On 

 July 8 abundance of aecia appeared, without being preceded by 



For previous cultures see Mycol. i: 240. 1909. 

 ^ Bull. Torrey Club 35: 503. 1908. 

 For previous cultures see Mycol. i: 253. 1909. 



