THE ALTERNATE STAGE OF PUCCINI- 

 ASTRUM HYDRANGEAE 1 



J. F. Adams 



Arthur (i) reports the genus Pucciniastrum as represented by 

 nine species in North American Flora. At that time (1907) the 

 aecial stage for none of the species was known in this country, 

 and for only one of them in Europe. Since the publication of 

 that part of the Flora two species have been connected with a 

 Peridermium stage by American investigators, and one other, P. 

 sparsum (Wint.) Bd. Fischer (3), by a European investigator. 



In the summer of 191 1 Fraser (4) was first to report success- 

 ful inoculations in this country between the aecial stage of Puc- 

 ciniastrum pustulatum (Pers.) Diet, on Abies balsamea and the 

 telial stage on Epilobium angustifolinm. In 1916 Weir and 

 Hubert (6) reported successful inoculations of Abies lasiocarpa 

 with telia of Pucciniastrum pustulatum. The aecial relationship 

 had previously been established abroad by inoculations by Bubak, 

 Fischer, Klebahn and Tubeuf (5). 



Clinton (2) in 1910 was the first to report successful inocula- 

 tions with the aecia of Peridermium Peckii Thum., and estab- 

 lished its relation with Pucciniastrum Myrtilli. Fraser in 1910 

 established the relationship between Peridermium Peckii and 

 Pucciniastrum minimum (Schw.) Arth. Prof. C. R. Orton and 

 the writer in 1914 successfully cultured Peridermium Peckii on 

 Azalea nudiflora, Vaccinium angustifolium and Gaylussacia sp. 

 These results indicate the relationship between these two forms 

 of Pucciniastrum on Ericaceous hosts and are such that they 

 may be identical. 



The writer collected material of Pucciniastrum Hydrangeae 

 (B. & C.) Arth. on Hydrangea arbor escens L. at Bear Run, 

 Lamar Gap, Clinton County, Pa., July 28, 1917, which is the first 



1 Contribution from the Department of Botany, Pennsylvania State Col- 

 lege, No. 19. 



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