g Art. 5.— Y. Toda: 



From August to October, the soil in the cave was wet, and 

 the growth of the shoots and of the protonemata was very active. 

 From December to January, on the contrary, owing to the com- 

 bined effect of lower temperatm^e and decreased humidity, the 

 protonema was in an inactive condition and the reflection of hght 

 from it was hardly perceptible. On the approach of spring, liow- 

 ever, the moss again began to thrive with the increase of tempera- 

 ture and humidity of the soil and air, forming sporangia at the 

 end of March. 



Temperature. — In August, the moss attained its full growth, 

 producing protonemata and shoots in abundance, and the phenom- 

 enon of the reflected light was most remarkable during this 

 season. 20^ to 25^0. seems to be the most suitable temperature 

 for the development of this moss, the mean temperature observed 

 at Yutanaka being 24°C. in August. Towards November, when 

 the mean temperature was 9. PC, the growth of the moss 

 graduaUy declined, and the reflection of light greatly diminished. 

 In January and February, when the mean temperature was as 

 low as —1.4 and — 0.9^C. respectively, the growth of the 

 moss naturally ceased. From the middle of March on, the 

 growth of tlie protonema was renewed and the reflected light 

 could gradually be noticed. In winter, I observed that the 

 temperature in the cave was always from 2" to 5^C. higher than 

 that at the Meteorological Station in this village. As the lowest 

 temperature in the viflage was — 11.5"C. this year, the minimum 

 temperature in the cave can be estimated as not lower than 

 -9.5^0. 



Assuming that in all the caves where the moss occurs, the winter 

 temperature inside the cave is always higher than that outside, 

 then the temperature in these caves would probably never be 



