Jan. 1010.] ORISHIMO.— ON THE CONNECTION. 3 



paniculata Thunb., Perilla nankinensis Dcne., Petasites japo- 

 nicus, Miq., Aster scaber Thunb., and Salvia japonica Thunb. 

 var. hipinnata Fr. et Say. 



I took seedlings of these seven species of host plants, and 

 planted them in 14 flower-pots separately, each containing two 

 seedlings of the same species ; thus I had two sets of pot-cultures 

 of the seven different species of host plants. I then covered 

 each of the pots with a glass bell-jar with its inside moistened 

 with wet blotting paper, the soil being kept moist by adequate 

 watering. After three days, on the 11th of May 1907, I sowed 

 a quantity of spores of Peridermium Pini-densiflorae and Pini- 

 Thunbergii, respectively on certain leaves of each seedlings in 

 different sets. Three days later, I placed these pots in a sunny 

 place under a frame of wire-netting. On the 2nd of June, i.e. 

 about three weeks after infection, I saw on the under surface 

 of the leaves of Aster scaber on which I had sown the spores 

 of Peridermium Pini-densiflorae, yellow spots consisting of the 

 sori of uredospores. After many days other spots appeared on 

 the other leaves of the same plant but it is apparent that they 

 consist of the secondary generations due to the infection of the 

 primary uredo-sori already formed. All the seedlings in the 

 other pots remaind unchanged and showed no sign of infection. 

 The first appearance of the teleuto-sori took place on the latter 

 part of August. From the above experiment, I was enabled to 

 know the probable existence of genetic connection between 

 Peridermium Pini-densiflorae and Coleosporium on Aster scaber, 

 which I had to acertein by the further infection experiments. 

 In these second experiments, I was also fortunate enough to 

 obtain a positive result. 



Experiment II. 



(Back infection.) 



In these cases, I have tried the back infection of the fungus 

 from Aster to Pine. For this experiment, I took two seedlings 

 of Pinus densiflora on the 10th of Septmber 1907, and planted 

 them in the flower-pots seperately, the one for infection and the 



