77 



produce the uredo as we'll as the teleutospore layers on the surface of the 

 leaves. 



In order to prove this fact experimentally, I took seedlings of three 

 species of Quercus, i.e. Quercus serraia, glandidifera and variabilis, and 

 planted them in six flower-pots separately, each containing 2-5 seedlings of 

 the same species ; thus I had 2 sets of pot-cultures of these three species 

 of quercus. 



I then covered each of the pots with a glass bell-jar with its opening 

 at the top plugged with cotton. 



The soil in the pots was always kept moist by supplying water from 

 time to time, and consequently the air in the bell-jar was saturated with 

 moisture. The results of experiments in last two years were essentially the 

 same, so I will mention here only that of last year. 



On the 30th of April 1898, I sowed a good deal of spores of 

 Peridermium giganteum on the upper surface of the leaves of the seedlings 

 in three of these pots, after moistening them with distilled water by means 

 of a spraying apparatus. I left the three other pots untouched for con- 

 trolling experiments. 



I then placed these six pots near a window facing the south. 



After 10 days, on the 9th of May, I saw on the under surface of 

 some of the leaves on which I had sown the spores yellow spots consisting 

 of the sori of uredospores beginning to appear ; and after 5 weeks heaps 

 of teleutospores began to be formed. 



These teleutospores immediately germinated on the leaves into 4-celled 

 promycelia, from each cell of which a spherical colorless sporidium was 

 produced (PI. V, fig. 13.) 



The form of the uredo-spore layer is circular in outline ; and its 

 pseudoperidium, which is composed of a felt of fine hypha?, is lacinated 

 in its ruptured margin (PI. V, fig. 11.) 



Plate V, Fig. 11 shows a vertical section of a uredolayer formed on 

 a leaf of Qicercus glandidifera. 



The structure of pseudoperidium of the uredolayer seem to me very 

 different from those of Cronartium flaccidura which is also common in 

 Tokyo, and also from those of the other known species of the same genus 

 given by Dietel in Engler's Naturlichen Pnanzenfamilien. 



In regard to this points, I intend to make a further investigation, 

 for I had no time to study them in detail this time. 



