Arthur: Cultures of Uredineae in 1908 253 



Blasdaleanum, being wholly lacking in Roestelial characters. The 

 aberrant form of the aecia is to a certain extent paralleled by the 

 unusual form of the telia, which led Dr. P. Hennings to describe 

 the telial stage as a Phragmidium. 



10. Gymnosporangium sp. nov. The series of circumstances 

 leading to the discovery of telia that made the present cultures 

 possible has been briefly narrated in the introductory paragraphs 

 of this report. On April 10, 1908, a collection was made at Mam- 

 moth Cave, Ky., by Mr. F. D. Kern and the writer, on the 

 branches of Juniperus virginiana, and on the following day a 

 growing plant of the same species only six inches high with large 

 sori on the main axis was obtained. The first collection was sown 

 April 13 on Porteranthus stipulatus (Gillenia stipulacea) , produc- 

 ing an abundance of pycnia April 21, but the plant did not thrive, 

 soon dying outright. Another sowing of the same material was 

 made April 15 on Porteranthus and also on Crataegus punctata, 

 with no infection on the latter, but very abundant infection on 

 the former, pycnia showing April 23, and aecia May 25. Another 

 sowing April 16 on Porteranthus gave such a heavy infection, 

 pycnia showing April 23, that the plant was soon killed. Still 

 another sowing April 27, and one April 28, gave very abundant 

 pycnia May 5, followed by numerous well-grown aecia that ma- 

 tured May 25 from the first sowing, and May 31 from the second. 

 The small plant of Juniperus had been potted, and continued to 

 thrive. Teliospores from this living plant were placed on a plant 

 of Porteranthus May 11, and on May 17 an abundance of pycnia 

 appeared, followed by numerous aecia that were mature by 

 June 7. 



The aecia from the cultures proved to be identical with those 

 collected by Rev. Demetrio in 1884, at Perryville, Mo., and issued 

 as No. 3323 in Rabenhorst-Winter, Fungi europaei. They are 

 especially remarkable in the fact that they occur on a non-poma- 

 ceous host, an herbaceous perennial, although heretofore the aecia 

 of all species of Gymnosporangium have been supposed to occur 

 exclusively on the ligneous plants of the family Malaceae. With 

 the aecia of this species going outside the Malaceae for its host, 

 and those of the preceding species falling outside the genus Roes- 

 telia, two of the most marked characteristics pertaining to the 

 first stage of the Gymnosporangia are shown to have exceptions. 



