g&l 



Arthur: Cultures of Uredineae in 1908 241 



published the same year. 82 Cultures have also been made since, 

 but most investigators in the discussion of their results have con- 

 fused this with other species. 



The form which has been most persistently confused in the 

 telial stage with the present species is what in Europe has been 

 called G. trcmelloides Hartig, which has much larger and other- 

 wise different telia on the bark of the larger branches of the same 

 species of juniper, but whose aecia are the true Roestelia penicil- 

 lata, and although occurring on Sorbns, are easily distinguished by 

 being fimbriate instead of horn-like. Mr. Kern 38 has recently 

 shown from partly circumstantial evidence that this species is the 

 TremcUa juniperina L., and should be called G. juniperinum (L.) 

 Mart. This disposition of the name, G. juniperinum, appears to 

 leave no available name under Gymnosporangium for the present 

 species, and a new combination is therefore necessary. The ear- 

 liest specific name is that given by Persoon to the aecial form in 

 1791, Aecidium comutum, the first species listed under the newly 

 established genus Aecidium. 



The other form included by European investigators with the 

 present species has very small telia on the leaves of the same 

 juniper, and horn-like aecia on Aronia. This is discussed in 

 the following paragraphs under the name G. Davisii Kern. 



22. Gymnosporangium Davisii Kern. It is with more than 

 usual satisfaction that I report the successful culture of this rust, 

 as it completes a knowledge of the life cycle of a trio of species 

 known to some extent in both Europe and America for many 

 decades, but much confused and misunderstood. The telia occur 

 on the leaves of Juniperus Sibirica, and have been sent in previous 

 years by Dr. J. J. Davis, from Wind Lake near Racine, Wis., but 

 could not be made to germinate. A collection made in the same 

 locality on May 24, 1908, by Dr. J. J. Davis and Mr. F. D. Kern, 

 was sown May 25 on Aronia nigra, Amelanchier crecta and Sor- 

 bus americana, with infection only on the Aronia, which showed 

 pycnia June 12, and well matured aecia Sept. 17. Another sow- 

 ing was made May 25 on Aronia nigra, producing a few pycnia 



83 Overs. Danske Vid. Selsk. Forh. 1866: 185-196. pi. 3, 4, with full 

 abstract in Bull. Soc. Roy. Dan. Sci. 1866: 15-16. 

 83 Science 27: 931. 1908. 



