Jan. 1906] 
Cultures of Uredineae in 1905 
21 
These results agree essentially with those reported by Carle- 
ton, 24 who was able to infect Xanthium in eighteen and fourteen 
days, but could not infect Ambrosia. He says, however, that 
“in all these cases spermogonia preceded the teleutospores in the 
infected spots.” In connection with an account of cultures with 
Puccinia heterospora he adds that “numerous experiments were 
also made with other lepto species, including Puccinia Grindeiiae 
Pk., P. variolans Hark., P. Lygodesmiae E. & E., and P. Sher- 
ardiana Korn., with results similar to those above mentioned,” 
but he does not report the details of these cultures, if such they 
were. 
Taking the observations here recorded for P. Xanthii, espe¬ 
cially in connection with those for P. Silphii and P. Grindeiiae, 
reported below, it seems safe to assume that these species, and 
those quoted as mentioned by Carleton, belong to a group of 
rusts in which teleutospores and their resulting sporidia are 
the only spore-forms produced in the life-cycle, aecidia, uredo, 
and even spermogonia being wholly absent. 
The following nine species have never been tested before 
by the culture method, so far as the writer knows, either in this 
country or abroad. They embrace an interesting diversity of 
habit. Besides the grass and sedge forms, with which this series 
of cultures has been most concerned, there are two leptopucciniae, 
one micropuccinia and one brachypuccinia, also one of the grass 
rusts is chiefly interesting for its amphispores. 
1. Puccinia Silphii Schw. — Teleutosporic material was 
gathered March 31, 1905, near Lafayette, Ind., on dead and 
weathered leaves of Silphium integrifolium, and sown April 10 
on vigorous plants of the same host, and also on S', perfoliatum. 
There was no infection on the latter host, but on the former 
clear yellow dots showed April 15, which sectioned and placed 
under the microscope proved to be very young teleutosori. 
These yellow dots rapidly enlarged, forming pale pimples scat¬ 
tered over yellow patches of the leaf, with much hypertrophied 
tissues, and April 20 broke through the epidermis, exposing the 
abundant teleutospores. Another sowing on the same two hosts 
was made April 25, and with the same results: there was no 
infection of .S’. perfoliatum, and the most abundant infection of 
S. integrifolium, showing as yellow dots May 2, and exposed 
teleutospores May 5. As the rust occurs on both these species 
of Silphium, and many others as well, the results may be taken as 
indicative of biological races. 
2. Puccinia Grindeliae Pk. — Excellent teleutosporic ma¬ 
terial on Gutierrezia Sarothrae was sent by Mr. Bethel, collected 
24 Bulletin Bureau PI. Industry, No. 63:26. 1904. 
