312 
Journal of Agricultural Research 
Vol. II, No. 4 
Table IV .—sEcial inoculations with Puccinia ellisiana , P. ellisiana from Pentstemon, 
and P. andropogonis —Continued 
PUCCINIA ANDROPOGONIS 
Species inoculated. 
AScial ancestral host. 
Date of 
inocula¬ 
tion. 
Degree of infection. 
Uredi- 
nia. 
Andropogon virginicus. 
Do. 
Pentstemon laevigatus, 1912.. 
Pentstemon laevigatus, 1913.. 
Pentstemon laevigatus, 1914.. 
Pentstemon laevigatus, 1912.. 
Pentstemon laevigatus, 1913.. 
Pentstemon laevigatus, 1914.. 
Pentstemon laevigatus, 1912.. 
Pentstemon laevigatus, 1913,. 
Viola papilionacea, 1914. 
Pentstemon laevigatus, 1912.. 
Pentstemon laevigatus, 1913.. 
Viola papilionacea, 1914. 
1914 - 
May 32 
•June 1 
May 22 
•May 29 
Very vigorous. 
Vigorous. 
1914 - 
May 30 
June 15 
June 1 
June 12 
Do. 
Good... 
Do. 
.do. 
DISCUSSION OF DATA 
These tables show that the cycle from a graminaceous host back to a 
graminaceous host was completed for each species of rust under discus¬ 
sion. They also show that Puccinia ellisiana was carried over to Pent¬ 
stemon, then to Andropogon, then back to both Pentstemon and Viola, 
and that this was done with pure pedigreed material grown under control 
conditions at the greenhouses of the Department of Agriculture, Wash¬ 
ington, D. C. The cultures made in 1913 with Puccinia ellisiana show 
that the teliosporic stage of this rust is able to infect both Viola (its 
usual host) and Pentstemon (the common host for Puccinia andropo¬ 
gonis) . These results were duplicated with pedigreed greenhouse mate¬ 
rial in the culture experiments made during 1914. The material used 
in 1914, as previously noted, came from six different sources. The 
material from five of these sources was pedigreed, and from three was 
both pedigreed and grown under control conditions. Precaution was 
taken to prevent contamination of the culture material and cultures 
throughout all of the experiments made in 1913 and 1914. The culture 
teliosporic material used was carefully checked under the microscope to 
further insure its purity. In no case were any signs of contamination 
found. The characteristic urediniospores for each rust were never found 
in the culture material of the other. 
The author fully realized that on the purity of his teliosporic culture 
material would depend the validity of his entire series of experiments; 
hence every effort was made to prevent contamination, and apparently 
these efforts met with complete success. It was to prevent any chance 
contamination vitiating the experiments that material was used from 
so many (six) different sources, as it was very improbable that pedigreed 
material from widely separated areas would all be contaminated. The 
teliosporic material of Puccinia ellisiana from each of the six sources 
infected the Pentstemon plants and also infected the various species of 
