78 



Still more favourably placed in legaid to the C().^ supply are 

 Ihe mosses j)resse(l inlo Ihe ground, the liver-niosses, and the 

 algae. Probably they llius oblain compensalion for the very weak 

 light. The foUowing exampie will show with what incredibh' small 

 qiianlities of light ceiiain mosses are abie to manage. 



At Hofs Hallar Ihere is a narrow cave, about 10 metres deep, 

 with a gently sloping bottom. Right at the back of this were 

 found quile numerous specimens of Schizostega. They stood under 

 a light-inlensilj' of ^1^ at a maximum, and only during a short 



1'hoto, the author. 

 Fig. 8. An association ot ferns and Maja/tfhemum bifolium in the Kapell hamn-bog. 



time on sunny days could they enjoy even so much light. The 

 atmosphere of the cave was probably very rich in CO.^. 



The assimilation values used in the calculalion of the ecological 

 light-minimum of the shade-planls apply to a temperature of IS'' C. 

 At a higher or lower temperature the intensily of assimilation is 

 increased or diminisbed respectively, but since the respiration also 

 shows a similar dependence upon the temperature, the ecological 

 light-minimum is probably not appreciably altered by changes of 

 temperature. 



