July 1904] Cultures of Puccinia Thompsonii Hume. 
17^ 
CULTURES OF PUCCINIA THOMPSONS! HUME. 
W. A. KELLERMAN. 
In default of guiding clues random cultures were made in 
1903 with the teleutospores of Puccinia thonipsonii Hume, a 
widely occuring rust on Carex frankii, but no success attended 
the attempted inoculations. Suspecting a possible connection 
with the Aecidium of the Elder, Sambucus canadensis , and not¬ 
ing the strong morphological resemblance between this species 
and the forms previously described as Puccinia bolleyana by 
Saccardo (1891) and Puccinia atkinsoniana by Dietel (1897)/ 
attempted inoculations were renewed the present season. 
Partially successful results were at first discredited in spite 
of the strong suspicion entertained that the alternate form would 
prove to be none other than Schweinitz’s Aecidium sambuci. 
At this time I communicated my suspicion to Dr. Arthur, also 
asking for good culture material in case he had any to share with 
me. Pie kindly returned answer at once, stating that he had en¬ 
tertained such an opinion for nearly two years as suggested above 
though he had no suitable teleutospores for inoculation. 
I was fortunate enough to find a small quantity of the Rust 
that had been exposed all winter, in the vicinity of Columbus. 
Proceeding with great care, most satisfactory results were ob¬ 
tained in a few days, when several vigorous inoculated host 
plants of Sambucus canadensis were rendered fairly yellow with 
abundant spermogonia. In the usual time the plants exhibited 
the characteristic Elder aecidia — even the infection of petioles 
and stems causing distortions resulted from the inoculations. 
The evidence could not be denied by the most skeptical and I 
can therefore with confidence assert that Puccinia thompsonii 
Plume is a synonym of P. sambuci (Schw.) Arthur. 
It is interesting to note, after all, that the description given 
by H. Harold Hume in the Botanical Gazette, 29 1352, May 1900, 
differs in no marked or striking degree from those of P. bolley¬ 
ana and P. atkinsoniana. For example, the teleutospores are 
said to be “oblong clavate, 48-68 x 15-24/x,” whereas in P. bol¬ 
leyana they are given as “clavate-oblong, 45-55 x 20-25 /x,” and in 
P. atkinsoniana as “mostly clavate, 40-60 x 18-28 /x.” It is said 
[ 1 . c.] that this species, P. thompsonii, “somewhat resembles P. 
bolleyana Sacc., but differs from it in the more scattered, larger, 
oblong, lighter-colored sori and the somewhat longer and nar¬ 
rower spores.” Doubtless the slight discrepencies in the three 
descriptions are referable to conditions or phases of a temporary 
character or minor importance. 
Hhese were pronounced by Arthur to be one and the same species 
and the name Puccinia sambuci (Schw.) Arthur was applied. Cfr. Bot. 
Gaz. 35:15. Jan. 1903. 
