156 
as averaging about 20 per cent. loss in cotton. In place of more 
severe infection he placed the damage at about 70 per cent. 
Since the rust epidemic on cotton had entirely ceased some time 
before my arrival, there remained only two things for me to do 
with reference to the disease: to search for the possible alternate 
host and to look for other possible centers of cotton infection. 
In regard to the latter, I examined cotton at Mercedes, Kings- 
ville and Falfurrias, Texas (where Drs. Heald and Wolf had 
collected Aecidium gossypii on September 14, 1909*), but I did 
not find any evidence of the rust. 
The major portion of my time in the valley was dHeretore spent 
in searching for rusted grasses, etc., especially in the area of this 
year’s cotton rust epidemic. Besides collecting rusted grasses 
in and about Mission, I also collected grasses, rusted and other- 
wise, outside the area of known infestation, at Mercedes, Kings- 
ville and Falfurrias. I had hopes by so doing of finding hints 
as to the possible alternate host by the process of elimination. If 
some grass hosts were found to be abundantly rusted in the 
critical area around Mission and not rusted about Mercedes, for 
instance, we could draw the conclusion that one or more of these 
grasses might serve as the alternate host of the cotton rust. 
~ About six or seven grasses and about three or four other 
kinds of host plants were found at Mission to bear rusts. Only 
about three or four rusted grasses and a few other hosts bearing 
rusts were collected at Mercedes and other stations. These re- 
main to be critically examined. I hope to be able by these studies 
to obtain a more reliable basis for culture studies next spring in 
order to establish beyond doubt the alternate host of cotton rust, 
if there be any. I might add here that I was too late on the 
ground to obtain reliable evidence as to whether the cotton rust 
might be short-cycled. From the slight evidence which I have at 
hand, I should hazard the guess that the cotton rust is not short- 
cycled,7 but that it goes over, probably, to some grass host to com- 
plete its life-cycle, and that in the spring it jumps again from the 
grass by means of the basidiospores back to the cotton. 
* Bull. 226, Bureau Plant Industry, p. 56. 
+ Dr. Arthur has bon the same conclusion, as stated in his letter of 
August 16, as he succeeded in germinating the cotton rust spores in a 
manner to show ee aecial nature 
