Puccinia Geranii silvatici , Karst. 29 
germinate. Up to the 28th only a spore here and there 
germinated ; but on that date germination was general. 
Hence the spores are slow in commencing to germinate. 
(Expt. 2.) — Similarly I floated freshly gathered spores of the 
second crop on water in a watch-glass on the 13th June, and 
on the 15th (24 x 2 hours) noted that some, though not many, 
had germinated, and had produced sporidia. (Expt. 3). — As 
a comparative experiment I also placed some spores of the 
first crop, which I had collected on the 23rd March, in 
another watch-glass under exactly similar conditions. These 
germinated very freely, producing many more sporidia than 
the fresh spores of the second crop. 
(Expts. 4, 5.) — I transferred the sporidia from each watch- 
glass (Expts. 2 and 3) to two halves of a healthy plant 
bearing young leaves, which I had uprooted carefully on 
the 15th June, and had placed in a glass vessel with the 
roots in water. The plant was then kept in my laboratory 
under a glass shade. On the 25th the part inoculated with 
the sporidia of the first crop showed two distinct points 
of attack on one leaf, while the other part remained free 
from visible attack. On the 28th the former inoculated part 
showed other two small crops of pustules on the stems. The 
part inoculated with freshly gathered spores of the second 
crop remained free from any sign of attack so long that on 
the 1 2th July I removed it from under the shade, and left it 
naked on a shelf in my laboratory, and did not look at it 
again until the 22nd, when to my surprise I found one leaf 
typically crumpled, with numerous black teleutospore-pustules. 
(Expt. 6.) — The spores taken from the last were placed in 
water in a watch-glass on the 22nd July; but they refused 
to germinate, and I had evidently come to the end of the 
series of teleutospore-generations, and had reached those 
destined to lie dormant until the following spring. I pre- 
served some of these spores for use next spring; but un- 
fortunately they became mouldy, and were presumably killed, 
as they did not germinate in March. This unfortunate mis- 
hap has prevented my completing experimentally the whole 
