EXPERIMENTS UPON THE HETERGECISM OF THE UREDINES. 53 
With A Ecidium berberidis on wheat the three experiments per- 
formed were all entirely successful, the check plant remaining free 
from the fungus. Both the infected and the control plants in these 
last-named experiments were raised under bellglasses, and covered 
by them continuously, except for the few minutes necessary to per- 
form the infection, until the end of the experiment, so that the 
source of error from accidental atmospheric infection was reduced to 
a minimum. 
The culture of Peridermium pini on the common groundsel 
(, Senecio vulgaris) has with me been one of the most difficult to 
perform. After several successive failures, however, I succeeded 
in two instances in producing the Coleosporium. 
By the infection of Poa annua with the spores of A Ecidium 
tussilaginis , the Puccinia poarum of Nielsen was in three out of four 
cultures produced — a Puccinia hitherto unknown in Britain. 
Perhaps the most interesting of the series, however, was the 
production of ^Ecidium zonale on Inula dysenterica (also a fungus 
new to the British flora) by infection with Uromyces junci. This 
was successful in every experiment. The actual demonstration of 
this hetercecism had not hitherto, I believe, been made, although 
Fuckel # had the strongest ground for believing it to exist. 
In one of these experiments some fragments of Juncus obtu- 
sifflorus, with numerous pustules of Uromyces , in active germina- 
tion, on them, were placed upon the upper leaves of a plant of 
Inula dysenterica ; in the course of ten or fifteen days these leaves 
began to show the yellow spots, which were the forerunners of the 
Ecidium. By this time the plant had grown taller, and had 
developed fresh leaves above those on which the Juncus had been 
placed. The fragments of Juncus were then removed from the 
leaves, on which they had been in the first instance placed, to the 
healthy, recently expanded leaves above, where in due course the 
AZcidium was developed. It was very interesting to observe how 
the yEcidium could thus be produced in successive crops. 
Podisoma sabince and Rcestelia cancellata. 
Exp. 2. — Six pear seedlings had fragments of Podisoma sabince 
placed on each on 19th April ; on 6th May the spermogonia of 
Rcestelia cancellata appeared on them. 
Exp. 6. — Three pear seedlings were infected on the 13th 
April with Podisoma sabince ; on 24th April yellow spots appeared ; 
on 6th May spermogonia were abundant on all three plants. 
Exp. 10. — Four pear seedlings infected with Podisoma sabince 
on 14th April at 8 a.m. On 6th May every plant had spermogonia 
on it. 
Exp. 25. — 11th May. Some Podisoma sabince , which had been 
soaked for 48 hours in water in a watch-glass, was placed on some 
leaves of a pear tree in Mr. T. Pung’s garden. Having some 
doubt of the efficacy of the material, these leaves were reinfected on 
* Fuckel, “Symbol. Mycol.,” p. 61. 
