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 réle 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, Hemato- 
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, 
