hi THE COLOURS AND PIGMENTS OF PLANTS 67 
causes of the colours of flowers, for the three 
processes already mentioned as the factors in the 
production of autumnal coloration are precisely the 
same as the processes which produce the colours of 
flowers. If the tints of autumn arise naturally from 
the check to vegetation produced by the first breath 
of frost, then we may reasonably suppose also that 
the colours of flowers are also in origin the natural 
result of diminished vegetative power. 
Although in our climate the majority of our 
plants shed their leaves in autumn in a cloud of 
glory, yet we have of course some which retain their 
leaves for several years, or do not shed them all 
at once, being, as we say, evergreen. Even here, 
I however, the diminished vegetative power is frequently 
seen in the partial modification of the chlorophyll. 
The leaves of many evergreens assume a reddish 
colour in winter, and this is due to the partial dis¬ 
appearance of chlorophyll from the corpuscles, and 
its replacement by red oily drops, probably of 
lipochrome nature. These red drops disappear again 
in spring when the leaves assume their normal green 
colour. This red pigment differs from that of most 
autumnal leaves in being confined to the chlorophyll 
corpuscles, while in most cases a red colour is due to 
anthocyan dissolved in the cell-sap. 
Colours of Flowers and Fruits 
The subject of autumnal coloration leads up to 
the colours of flowers and fruits. These in the 
general case are due either to anthocyan pigments 
dissolved in the cell-sap, or to lipochrome pigments 
