6 o 
MILDEWS, RUSTS AND SMUTS 
produced on a living host-plant ; teleutospores germinating 
only after a period of rest. 
(1) Auto-Puccima. Pycnidia, aecidia, uredospores and 
teleutospores produced on the same host-plant. Ex. 
Puccinia galii. 
(2) Hetero-Puccini a. Promycelium-spores giving origin 
to aecidia on a different kind of host-plant from that on 
which teleutospores are produced. Ex. Puccinia graminis. 
B. Brachy-Puccinia. Pycnidia, uredospores and teleu¬ 
tospores produced on the same host-plant, aecidia absent. 
Ex. Puccinia ohtegens .(—P. suaveolens). 
C. Hem-iphucciiiia. LTedospores and teleutospores pro¬ 
duced on the same Lost-plant ; pycnidia and aeciclia absent. 
Ex. Puccinia polygoni. 
D. Pucciniopsis. Pycnidia, aecidia, and teleutospores 
produced on the same host-plant ; uredospores absent 
(or rarely a few mixed with the teleutospores). Ex. 
Puccinia tragopogonis. 
E. Micropuccmia. Teleutospores only produced, ger¬ 
minating only after a long period of rest, on the dead host- 
plant. Ex. Puccinia ribis. 
F. Leptopuccinia. Teleutospores only produced, ger¬ 
minating at once on the living host-plant. Ex. Puccinia 
malvacearum. 
INFECTION EXPERIMENTS 
From what has been stated, it is obvious that any one 
or more of the six known forms connected with reproduc¬ 
tion, may drop out, or be omitted, without in any way 
preventing the remaining spore forms belonging to the 
species from continuing their existence. On the other 
hand, it is highly probable, that any one of the spore forms, 
excepting pycnidia, is capable of perpetuating itself con¬ 
tinually. 
As previously stated, aecidia, uredospore and teleuto- 
spore forms were at one time considered as representing 
three distinct genera. Many of these have now been linked 
up, or proved to be genetically connected. At the same time, 
even in this country, there are many aecidium and uredo¬ 
spore forms that are not connected with other spore forms. 
The only method of ascertaining whether such isolated forms, 
as we know them, are in reality genetically connected with 
other forms, is by infection experiments, and for this method 
there is no general rule ; that is, when the different spore 
forms grow on different host-plants, it does not follow that 
