Physiological Studies on Schiitoilega os-numlaccn. 5 



from the south-east to the south-west, only one of them facing 

 due north. 



2. Nakabusa Hot Spring and Mt. Ariyake. — On the way 

 from Miyashiro to Nakabusa, tlie moss is found in successive small 

 caves for a distance of about 5 miles. On Mt. Ariyake, near 

 Nakabusa, it occurs in caves and in holes at the foot of fallen 

 dead trees, at a height of about 2250 m. above sea-level. The 

 rock consists of biotite granite, and the caves face various direc- 

 tions, only a few looking north. It was only in the above- 

 mentioned locality, near Nakabusa, that I found much of the moss 

 furnished with sporangia ; in other places the moss was almost 

 always found in a sterile condition. 



3. Yutanaka Hot Spring (Heion-mura). — On tlie banks of 

 tlie river Yamase, which runs through the southern part of the 

 village, there are four large caves (560 ra. above sea-level) facing 

 south-west, with gravel beds. 



Intensity of Light. — For determining the intensity of light, 

 I found Vouk's (9) photometer^' very convenient and easily portable. 

 With this apparatus I compared the intensity of light inside 

 the caves with that outside. For example, at Mt. Komagadake : 



L=- 77-— and at Nakabusa: L 



5 43.4 ^^^^^^^ 94.2 289.4 " 



For the caves at Yutanaka I estimated the " Lichtgenuss " 



about once in two months, from August 1914 to April 1915. 



The results may be seen in the following Table I. 



1) VcvK, V. : Ein verbesserter, nouer Wiesnerscher |Insolater zur liestimmung des Licht- 

 genusses (Ber. d. deutlich, bot, Ges. Bd. XXX, pp. 391—394. 1912). Compare al=o Wiesxer, J. '• 

 Der Lichtgenuss der Tflunzen il!>07). 



