86 
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 Carex filifonnis 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, 1911, 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, 1913, was sown April 
18, 1914, on Decodon verticillatus, 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 Aecidinni 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.) Earl. — Material on 
Chamaecy Paris thyoides was sent by Dr. Eromme from Lakehurst 
