Dec. 1903] UrecLineous Infection Experiments in 1903 225 
drical, 100-120 x 7 n. Sporidia uniseriate, oblong elliptical, 3- 
septate, scarcely constricted, olive-brown, 12-15 x 3J /*. The 
ostiola raise the bark into little pustules which are not very con¬ 
spicuous. 
This comes near P. comptonise E. & E. 
Diatrypella xanthostroma E. & E.—On dead limbs of 
Pirus japonica, London, Canada, Nov. 1903. (Dearness, 2045). 
Stroma tubercular-erumpent, 2-4 mm. diam. rather flattened 
on top and bearing adherent fragments of the ruptured epidermis, 
black outside, yellow within (the same shade of yellow seen in 
Hypoxylon sassafras Sz.) Perithecia 4-10 in a stroma, globose 
or slightly flattened laterally, subfarinaceous outside, about \ mm. 
diam., abruptly contracted above into short necks with variable 
ostiola, papilliform, conical, or obscure, finally rather broadly 
perforate above. Asci clavate-oblong, 55-65 x 8-10 n, polyspo- 
rous. Sporidia allantoid, yellowish-hyaline, slightly curved, 9-10 
(exceptionally 9-12 x 2 (i. 
This comes near D. frostii Pk. but the sporidia are longer 
and the yellow color of the stroma inside is different. 
UREDINEOUS INFECTION EXPERIMENTS IN 1903A 1 ) 
W. A. KELLERMAN. 
Artificial infection experiments with certain species of Puc- 
cinia and Uromyces, continuation of those published one year 
ago, are here reported for the current season, beginning March 
5th and ending June 18, 1903. Attention is called to the preced¬ 
ing report where explanations are made relative to the plan and 
execution of the work — substantially the same being followed 
during the season now under consideration. 
It may be mentioned that pre-season experimentation, or at 
least very early inoculations, proved very advantageous again, as 
in the preceding year. For example, in case of the demonstrated 
connection between Puccinia muhlenbergise Arth. & Holw. and 
Aecidium hibisciatum Schw., quite unexpected, repetition of the 
inoculation three times was possible, the last time with the host 
plants growing in their natural habitat. Had this not been pos¬ 
sible judgment would perhaps have been held in suspense, but 
under the circumstances a positive conclusion was not deferred 
to another year. 
Advantageous and desirable as it is to carry on germination 
tests before making the inoculations, I can not think it objection- 
( x ) Contributions from the Botanical Laboratory of the Ohio State 
University. XV. ' 
Presented before the Botanical Society of America, at St. Louis, 
December, 1903. 
