60 
Journal of Mycology 
[Vol. 11 
In addition to the foregoing results five species of rusts 
were grown, establishing aecidial and teleutosporic connections, 
not heretofore recorded. The species are heteroecious with one 
exception. 
i. Melampsora Bigelowii Thurn.— Three collections of 
teleutospores on Salix were secured, but only one, which was 
obtained at Racine, Wis., on Salix amygdaloides Anders., and 
forwarded by Dr. J. J. Davis, could be made to germinate. This 
was sown, May io, on Larix decidua Mill., and twenty days 
later both spermogonia and aecidia were observed in abundance, 
although they had probably first made their appearance some 
days earlier. On the same date it was sown on Euonymus 
obovatus without result. A further sowing on Larix decidua 
was made on May 25, and on June 4 spermogonia began to 
appear in great abundance, followed on June 10 by an equal 
abundance of aecidia. The aecidia are of the typical caeoma- 
form, and are very similar to those of Melampsora Medusae , 
the chief difference being in the spores, which are somewhat 
more distinctly and coarsely verrucose than in the poplar form. 
The only American collections of aecidia on Larix, that 
have come to my attention, were made by E. W. D. Holway 
at Mt. Temple, Aug. 22, 1902, and Laggan, Aug. 23, 1902, 
both places in Alberta, Canada, and both collections on Larix 
Lyallii Pari. These collections agree perfectly with the aecidia 
raised in cultures. A comparison of the numerous collections of 
willow rust in my own herbarium, numbering 80 packets, and 
representing all sections of the United States and Canada from 
the Atlantic to the Pacific, shows that both the uredosporic 
and teleutosporic stages agree closely with one another, and 
with those on the material used in the culture. 
A comparison with European collections shows the Ameri¬ 
can form to be very different from any European species. The 
nearest approach to the American form is Melampsora Larici- 
epitea Kleb., the most common willow rust of Europe. The 
two differ, however, in a very marked way. The American 
form has all three sorts of spores considerably larger, the spores 
of the aecidia and uredo have walls twice as thick, the pores 
are far more evident, and the papillae on the surface are much 
closer together. 
The name which I have adopted for this common willow 
rust was given by Baron von Thuemen to a collection made 
in California on Salix Bigelowii, which he stated had been 
received from the herbarium of Dr. W. G. Farlow. Von Thue- 
men’s herbarium was burned some years ago, and the type is 
consequently destroyed. In reply to an inquiry regarding the 
matter, Dr. Farlow states that he does not recall sending such 
a specimen to von Thuemen, and is unable to find a correspond- 
