56 OUR WOODLAND TREES. 
Purple and crimson too, and other hues and 
colours, are found oftentimes delicately mixed with 
the green of our leaves; and though the per- 
vading greenness is often so conspicuous that it is 
difficult to detect the presence of any other colour, 
much of our sense of enjoyment, occasioned by 
the contemplation of ‘lush greenery,’ doubtless 
arises from the beautiful though almost impercep- 
tible intermixture of other and lighter or darker 
shades. The gloss on the leaves of many plants 
is due to the extreme transparency and reflect- 
ing power of the surface walls of the superficial 
cells. 
The embryo plant, then, consists of a beautiful 
cellular frameworkenclosing a protoplasmic fluid— 
the part underground being, from the absence of 
the chemical influence of light, devoid of colour; 
the part above ground being by the chemical 
action of sunlight displayed in hues equalling in 
richness and exceeding in number, by intermixture 
of shades, those of the rainbow. We have seen 
what isthe structure and functionof the rootlets and 
roots, stem and leaves. They are all cellular tissue 
modified by circumstances, and, by Divine wisdom, 
