136 
James R. Weir. 
the main points of my study will be presented. The material was 
for the most part collected during the summer of last year. 
Methods. 
The material used was fixed chiefly by placing it for twenty-four 
hours in Flemming’s stronger solution, nearly all material was fixed 
in the field. Specimens were also brought into the laboratory for 
germination experiments. After fixing, the material was then 
washed in running water for several hours, dehydrated, passed 
through chloroform and then embedded in the usual manner. For 
staining, Flemming’s triple stain was used. 
By keeping the teleutospore material in a cooling chamber, the 
germinating power was retained for several weeks. If the leaves 
with the masses of teleutospores are placed on well saturated filter 
paper under a bell jar at a temperature of 20°C, germination takes 
place very readily. Such cultures made in the evening always 
produced on the following morning abundant sporidia. At ordinary 
room temperature the teleutospores germinated freely, the sori 
losing their waxy appearance and under the s. m. showed as spongy 
masses due to the growth of the germ tubes. The germinating 
experiments were also conducted in hanging drop cultures in 
Vantugam cells. 
The Teleutospore. 
The teleutospores appeared through the greater part of the 
fall, and are found in dense rounded or oblong orange yellow sori, 
sometimes almost covering the entire under surface of the leaf. 
The young spore is always a single cell and contains two nuclei, 
the result of a division of a pair of nuclei in the mother cell. The 
spore possesses a delicate exosporium, which has more of the 
appearance of a plasma membrane than a spore wall. Usually the 
spore about doubles in volume. The nucleus becomes very large 
and about this time the young spore is cut off from the mycelial 
cell by a cross wall. The nuclei increase in size, at the same time 
approach each other and begin to fuse. At this stage the nuclei 
seem to become more granular or open. The chromatin threads 
are spread more uniformly about the nucleoli and are characterized 
by a much smoother outline than they possessed in the former 
conjugate stage. When the two nuclei come together the nuclear 
membrane at the point of contact disappears, and finally no line of 
separation can be distinguished. They continue to fuse until the 
entire membrane is absorbed and we now have a single large round 
nuclear mass. After fusion the teleutospore is stimulated to growth 
at once, and forms the promycelium. 
