26 PLANT LIFE 



stance that they are able to utilise light of low 

 intensity which pases through the interspaces 

 of the leaves of the trees above. 



It turns out also that the chlorophyll green 

 is destroyed by the same rays that are photo- 

 synthetically active, and this destruction is 

 without doubt intimately connected with its 

 function in relation to such rays. It does not, 

 however, follow, nor indeed is it probable, that 

 the role of chlorophyll is a very direct one in 

 influencing all the stages of photosynthesis. 

 It is more likely that its primary function is 

 concerned with the earliest stages, utilising 

 the energy of the absorbed light, and thus 

 providing the conditions for starting those 

 processes of chemical change which, under the 

 influence of protoplasm, culminate in the 

 formation of the higher carbon compounds. 

 For, so far as is certainly known, it is only 

 when chlorophyll is united with the living 

 substance that these higher compounds are 

 able to make their appearance. 



When the green chlorophyll matter is decom- 

 posed in a living plant cell, other colours, 

 commonly red or a rusty orange, make their 

 appearance. A striking example of this is 

 furnished by the red snow plant, Hcemato- 

 coccus nivalis. This unicellular alga is closely 

 related to species of Chlamydomonas, and 

 indeed by some writers is included in that 

 genus. It exists in a green and a red form, 

 and is either motile, like Chlamydomonas, 

 or it may pass into a non-motile resting stage, 



