86 2l4 x 5 Mycologia 



and another April 15, with no result. A third sowing on April 25 

 was better done, and gave rise to pycnia on the leaves May 6, and 

 aecia May 20. 



Aeciospores from this culture were sown May 26, which re- 

 sulted in the production of uredinia June 15, not numerous but 

 well formed. Uredinia continued to be produced until they were 

 finally followed sparingly by telia July 10. 



In every sowing an abundance of spores was used, which were 

 applied to both leaves and stems. Tests of the spores showed 

 unusually strong germination. Why the infection was so spar- 

 ing and only on the leaves, while in the field the rust is chiefly 

 on the stems, was not apparent. The cultures supply a knowledge 

 of the pycnia and uredinia, neither of which were before known. 



4. Puccinia minutissima Arth. Viable material of this spe- 

 cies on Car ex filiformis was secured at much labor especially for 

 this work by Mr. J. Dearness of London, Ontario, from the 

 southeastern shore of Lake Huron. A collection made in De- 

 cember, 191 1, was sown the following spring on seven hosts 

 of as many genera without infection. Another collection of May, 

 1912, was similarly tested, and even more thoroughly, without 

 success. A collection made in November, 191 3, was sown April 

 18, 1914, on Dccodon I'crticillatus, with an abundant infection, 

 showing pycnia April 27, and aecia May 7. 



The first suggestion for this connection was made by Prof. 

 James B. Pollock of the University of Michigan, who wrote on 

 August 3, 1909, as follows : " I found a rust on a patch of Carex 

 filiformis, forming a half circle with a radius of about two rods 

 around a specimen of Decodon verticillatus, some of whose leaves 

 had an Aecidium on them. I send herewith specimens of both. 

 No other Aecidium was found near the rusted sedge. The whole 

 situation seems to me to indicate very closely the Decodon plant 

 as a center of infection for the Carex rust." 



The aecial stage of this rust is Aecidium Nesaeae Ger., but 

 Puccinia Nesaeae Ellis & Ev. does not belong here, having been 

 founded on a telial collection with the host erroneously deter- 

 mined. The error was detected by Prof. E. W. D. Holway. 



5. Gymnosporangium Ellisii (Berk.) Farl. Material on 

 Chamaecyparis thyoides was sent by Dr. Fromme from Lakehurst 



