Jan. 1905 ] Uredineous Infection Experiments 
29 
NO BIOLOGICAL SPECIES OF PUCCINIA SORGHI. 
It will be noted that the six so-called “agricultural species” of 
Maize, namely Zea everta (or Pop Corn), Zea indurata (Flint 
Corn), Zea amylacea (Soft or Flour Corn), Zea saccharata 
(Sweet Corn), Zea indentata (Dent Corn), and Zea tunicata 
(Pod Corn) were used as hosts and with equally successful re¬ 
sults. The teleutospores and uredospores were applied as detailed 
above. The conclusion seems to be warranted that there are 
no “biologic” species in case of the Maize Rust known as Puccinia 
sorghi Schw. 
A NEW HOST FOR PUCCINIA SORGHI. 
Seeds of Teosinte, Euchlsena luxurians, were furnished me 
by the U. S. Department of Agriculture and thirty young plants 
were soon available for purposes of inoculation. Using the uredo¬ 
spores obtained by an early inoculation of the season, making 
the sowings May 15, good infection was exhibited May 24, an 
abundance of uredospores present at that date. Another infection 
was made June 4 on this species as host and on June 15 a uredo 
pustule appeared. So far as I am aware this host has not here¬ 
tofore appeared in literature. 
UNSUCCESSFUL RESULTS ON OTHER HOSTS. 
When Schweinitz published his description of Puccinia sorghi 
he said as to its occurrence: “frequens in foliis Sorghi et Zese.” 
Under apparently favorable circumstances many inoculations were 
attempted with Sorghum vulgare, Saccharum officinarum and 
Tripsacum dactyloides, all of which were unsuccessful. 
Roots of Tripsacum were removed to the greenhouse very 
early in the spring and numerous vigorous plants were available 
for the inoculations May 15 and on later dates (Expts. 354, 365, 
380, 391, 396, 400, 405), but in no case were the efforts rewarded 
with success though uredospores were used from sori which 
furnished the inoculating material for the successful inoculation 
on Maize plants. 
Seedlings of Sorghum vulgare, both common Sorghum and 
Broom Corn, were inoculated with tested uredospores and yet 
all the attempts failed. It appears that this host when grown 
in the greenhouse is invulnerable to Puccinia sorghi from Maize 
(Expts. 359, 360, 362, 397, 399, 403, and 404). 
A living plant of Sugar Cane, Saccharum officinarum, was 
kindly sent me from Mississippi by Prof. S. M. Tracy. After 
recovery from the shock of transplanting, inoculation with uredo¬ 
spores similar to material used in previously successful cultures 
was not successful. 
