Puccinia Geranii silvatici, Karst . 31 
(Expt. 12.)— Having uprooted a healthy plant, and having 
placed its roots in a glass vessel containing water, I inoculated 
it freely on the 25th April with sporidia from a cultivation 
started on the 23rd, and kept it in my laboratory under a 
glass shade. On the 4th May (nine days) I noticed several 
foci of attack on three leaves ; but there was as yet no spore 
eruption. On the 9th May (fourteen days) the plant was very 
extensively attacked in leaves, petioles, and stems, with 
marked hypertrophy of the latter, and large spore-eruption 
(Fig. 1). (Expt. 13.) — On this date I removed some spores 
and placed them in water as a parallel cultivation with that 
described above (1). On the 10th none had germinated, but 
on the 13th (24x4 hours) germination was free, though not 
quite so general as in the parallel cultivation. This was 
probably due to many of the spores being much younger and 
more immature. 
These experiments prove that the spores of the first (Expts. 
1, 3, 7, 8, 9, 11, 13) and second (Expts. 2 and 6) crop are both 
Micropuccinia and Leptopuccinia ; and that the fungus is 
complete and autoecious with teleutospore-formation only 
(Expts. 4, 5, 10, and 12). I venture to think that the estab- 
lishment of the former point, namely the power the spores of 
each crop possess of both germinating at once and after rest, 
more or less prolonged, is important, since it shows that 
Schroter’ s divisions Lepto- and Micro-puccinia, though they 
may prove useful artificial classes in those cases in which the 
life-histories are unknown, are not based on fundamental 
biological facts as he supposed. Schroter writes 1 that the 
mycelia produced by sporidia derived from teleutospores 
which have passed through a period of rest bear spermogonia 
and aecidia, while those produced by sporidia derived from 
teleutospores which have germinated at once bear only teleu- 
tospores again. With reference to the former proposition we 
have here an experimental demonstration that the sporidia of 
even over-wintered teleutospores can reproduce teleutospores ; 
1 Die Pilze Schlesiens, page 297. 
