TELEUTOSPORES 11 
both (Fig. 12). The uredospore retains its capacity for 
germination for a longer time, even: . 
for more than three months; in fact, 
in certain foreign species, some of these 
spores acquire a thicker wall which 
enables them to act as a kind of 
resting-spore—these are called amphi- 
spores, but they are not formed by 
P. Caricis. 
It is found, generally, that if the 
spores of the Uredinales are dried 
gradually, they retain their power of 
germination for a longer time and in 
a better degree than if dried quickly 
or not dried at all. Most likely a slow Fig. 12. Two uredospores 
of P. Caricis, both germi- 
drying enables them to mature more nating in distilled water. 
perfectly. laa 
THE TELEUTOSPORES. 
After a time, probably in response to the weather or other 
change of environment, the mycelium which has hitherto given 
rise only to uredospores begins to produce, at first in the same, 
afterwards in separate sori, the fourth kind of spore—the 
teleutospore. In the genus Puccinia this is almost always a 
compound body, formed of two superposed cells; each cell is 
really a spore, and is capable of independent germination. In 
many species of the genus the teleutospores readily break 
apart at the septum, eg. in Puccinia fusca and P. Pruni- 
spinosae, and the lower half may be, and has been, mistaken for 
a uredospore. Those of P. Caricis do not easily break apart 
until they are old and dead. 
The teleutospores are formed on a pedicel, much in the 
same way as the uredospores, except that the uppermost cell 
is again divided, but apart from that they differ widely in 
their character. They have a thick dark-brown exospore, 
covered with a chitinous cuticle; in this species the exospore 
