Hedgcock and Hunt: Notes on Coleosporium 245 



of the connection of this aecial form with the Coleosporium on 

 species of Coreopsis in 19 13 3 led to the separation of Coleosporium 

 inconspicuum (Long) Hedge. & Long from Coleosporium heli- 

 anthi. The discovery of the aecial form of Coleosporium helianthi 

 by the senior writer in 1914, and the publication of the proof of 

 its relation to the Coleosporium on species of Helianthus in 191 7, 4 ' 5 

 leaves in the eastern United States the forms of Coleosporium on 

 Verbesina and Viguiera without proven aecial forms. 



Inoculations with Coleosporium helianthi 



The superficial resemblance of the aecia of Coleosporium heli- 

 anthi (PI. 20, fig. 2) to those of Coleosporium inconspicuum (PI. 

 20, fig. 1) has necessitated extensive inoculations with the aecio- 

 spores from both forms, the results of which will now be given. 6 

 Fortunately several of the earlier collections of the aecia of Coleo- 

 sporium helianthi were from localities either where species of 

 Coreopsis were not present, or were not infected with Coleospo- 

 rium if present, and several collections of Coleosporium incon- 

 spicuum were obtained from localities either where species of 

 Helianthus were not present, or if present were not infected. 

 This afforded an opportunity to experiment with reasonably pure 

 natural stocks of each rust. Later these results were verified by 

 the use of aeciospores from pedigreed aecia obtained by inoculating 

 in separate experiments trees of Pinus virginiana with the telia of 

 each species of Coleosporium. 



From 1914 to 1921, twelve sets of inoculations were made with 

 the aeciospores of Coleosporium helianthi and from 191 5 to 1921, 

 fourteen sets with those of C. inconspicuum in the greenhouses at 

 Washington, D. C. As in all our inoculation experiments with 

 aeciospores and urediniospores of species of Coleosporium, the 



3 Hedgcock, G. G., & Long, W. H. Notes on Cultures of Three Species of 

 Peridermium. Phytopathology 3: 250, 251. August, 1913. 



4 Hedgcock, G. G., & Hunt, N. R. An Alternate Form for Coleosporium 

 helianthi. Phytopathology 7: 67, 68. February, 19 17. 



5 Hedgcock, G. G., & Hunt, N. R. New Species of Peridermium. Mycolo- 

 gia 9: 240, 241. July, J917. 



6 Dr. Wm. H. Long assisted the senior writer during 1913 and 1914, and 

 Mr. N. Rex Hunt from 1915 to 1918. 



