Dec. 1903] Uredineous Infection Experiments in ipoj 
231 
lows: “Culture experiments were also performed with the 
common Sunflower Rust, which showed that the Puccinia and 
Aecidium found on Sunflower are stages of one and the same 
species. At the same time it is made probable that all the 
species of Helianthus affected bear the same Rust and that there 
is no distinction of host forms.” 
Dr. Arthur sowed teleutospores from Helianthus grosse- 
serratus Mart, on the same host and on H. maximiliani Schrad.; 
cultures successful. He adds that sowings at two different dates 
on H. strumosus gave no infection. 
Such facts on record induced me to make as large number 
of cultures as possible, hoping to furnish worthy testimony in 
the case. But my success was slight, my failure was great. I 
used teleutospores from three species of Helianthus as stated 
above. Inoculations were attempted on nineteen species as hosts, 
namely, H. annuus, atrorubens, decapetalus, divaricatus, doroni- 
coides, gigantea, grosse-serratus, hirsutus, kellermani, laetiflorus, 
longifolius, maximiliani, mollis, multiflorus, orgyalis, strumosus, 
subtuberosus, tracheliifolius, and tuberosus. 
I am sorry to record that the only successful inoculations 
were those with teleutospores of Helianthus mollis Lam. on H. 
annuus and LI. mollis. A few inoculated leaves of each of these 
two species produced a small number of aecidia. Repetitions 
with this and other inoculating material were unsuccessful — and 
the reason for such failure is not clear. The material in case of 
H. annuus was unfortunately quite small in quantity and at the 
time not considered satisfactory. That from IT. decapetalus and 
H. ambiguus was abundant but the quality was suspected. But 
that from H. mollis was apparently in good condition. It had 
been exposed in the natural habitat all winter, and collected April 
2, near Sandusky, Ohio. In spite of the above I do not at all 
think the negative results of great significance. Of course this 
Rust on H. mollis will grow on H. annuus, but I do not suppose 
it will necessarily fail to grow on others — in fact I fully believe 
at the hands of other experimenters or under other conditions 
more abundant success will be vouchsafed. It may be well 
briefly to record the data of the experiments. 
Expts. 100-114. April 5. Teleutospores from Helianthus mollis Lam., 
applied to Helianthus mollis Lam., annuus L., giganteus L., 
laetiflorus Pers., hirsutus Raf., tuberosus L., orgyalis DC, 
divaricatus L., mollis Lam., tracheliifolius Mill., strumosus 
L., atrorubens L., kellermani Britt., and grosse-serratus Mart. 
Spermogonia appeared on H. annuus L. {Exp. ioi ) April 18 , 
and aecidia April 24 ; ditto H. mollis Lam. {Exp. 109). 
Expts. 170-179. May 24. Same to Helianthus mollis Lam., laetiflorus 
Pers., maximiliani Schrad., orgyalis DC., kellermani Britt.,, 
hirsutus Raf., tuberosus L., giganteus L., subtuberosus Bourg.,. 
longifolius Ph. No infection.. 
