CULTURES OF UREDINE IN 1899." 
EG CAP THU Re 
WitH the exception of the very important results achieved 
by Thaxter in the study of American Gymnosporangia, together 
with similar work by Farlow, Halsted, Stewart, and Carver, only 
a few attempts have been made in America to trace the connec- 
tion experimentally between the forms of the Uredinee. 
The three stages of the clover rust (Uromyces Trifolit) were 
shown by Howell to be genetically connected and the two 
forms of the raspberry rust ( Gymnoconia interstitialis) by Clinton. 
A slight amount of work in this line of research, chiefly of a con- 
firmatory character, was carried out between 1889 and 1898 by 
Bolley, Stuart, and the writer. The yet unpublished results of 
Carleton, obtained as part of the work of the division of vege- 
table physiology and pathology at Washington,’ complete the 
mention of all American efforts in this line that now occur to 
the writer. 
The cultures made during the present season (1899), herein 
to be described, were conducted, with the exception of a single 
trial, under glass in the greenhouses of the Experiment Station 
at Purdue University, and upon plants in pots, the plants remain- 
ing under cover until the observations were completed. Material 
bearing teleutospores of a number of species was collected dur- 
ing the previous autumn and winter and preserved until needed 
by tying in loose muslin and placing on the ground out of 
doors. 
The method generally adopted to secure infection was the 
same, whether zcidia, uredo, or teleutospores were in hand. 
The potted plant was first wet with an atomizer, parts covered 
with a bloom being rubbed with the fingers until the watet 
* Read before the Botanical Section of the Am. Assoc. Adv. Sci., Columbus meet 
ing, August, 1899. 
? Issued as Bulletin No. 16 since the paper was read. 
268 [aRPIL 
