Jan. 1905] 
Uredineous Infection Experiments 
33 
at once, stating that he had entertained 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 obtained in a few days, 
when several vigorous inoculated host plants of Sambucus canadensis 
were rendered fairly yellow with abundant spermogonia. [Expt. 326.] 
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 thomp- 
sonii Hume 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, 29:352, May 1900, differs in no 
marked or striking degree from those of P. bolleyana and P. atkin- 
soniana. For example, the teleutospores are said to be “oblong clavate, 
46-68 x 15-24 whereas in P. bolleyana they are given as clavate- 
oblong, 40-60 x 18-28 v.” It is said [1. c.] that this species, P. thomp- 
sonii, “somewhat resembles P. bolleyana Sacc., but differs from it in the 
more scattered, larger, oblong, lighter-colored sori and the somewhat 
longer and narrower spores.” Doubtless the slight discrepancies in the 
three descriptions are referable to conditions or phases of a temporary 
character or minor importance. 
UNSUCCESSFUL EXPERIMENTS. 
Other Rusts were tested as Puccinia emaculata, P. osmor- 
rhizae, P. asparagi, P. curtipes; Rusts from Carex intumescens, 
C. laxiflora, C. pubescens, etc., but the failures are not instructive 
and need not be reported in detail. 
SUMMARY. 
Puccinia sorghi Schw., teleutospores, was shown capable 
of directly producing uredospores — no spermogonia or aecidia 
appearing. 
This Rust (uredo stage) was readily and indiscriminately 
transferred to the six ‘agricultural species’ of Maize, Zea mays 
amvlacea, everta, indentata, indurata, saccharata, and tunicata. 
Hence there are no ‘biologic forms’ of Puccinia sorghi Schw. 
This species was successfully grown on Teosinte, Euchlaena 
Inxurians, which is a hitherto unreported host. 
Attempted inoculation of Sorghum vulgare, Saccharum offi 
cinarum, and Tripsacum dactyloides were unsuccessful. 
Rust from Helianthus tuberosus (Artichoke) was suc¬ 
cessfully used in inoculating Helianthus annuus, showing that 
the so-called Puccinia helianthorum Schw. is the same as Puc¬ 
cinia HELIANTHI SCHW. 
Teleutospores of Puccinia thompsonii from Carex 
frankii were grown on Sambucus canadensis — showing that 
this Rust is Puccinia sambuci (Schw.) Arth. 
Peridermium pini was used in a successful inoculation of 
Campanula americana — showing that this form is contained in 
the life cycle of Coleosporium campanulae (Pers.) Lev. 
