Roses and Apples a2 
which give the tree a very handsome appearance in 
autumn, when birds swarm upon it and quickly 
devour the fruit. 
There is yet one other of the Apple section of Roses 
to which we must refer, and this is perhaps the most 
familiar and plentiful of all. It is the haw,—the 
fruit of the Hawthorn or May (Crategus oxyacantha), 
—and from the outside it is not much unlike the 
Rowan-berry. Its few-berried clusters stand erect 
instead of drooping, and its “core,’ very hard and 
bony, is composed of one or two, occasionally three 
carpels, with very little flesh outside. 
If we take a glance at the leaves of all these species 
we shall find great variety in their forms, and this 
variation appears to be dependent upon the manner 
of their arrangement on the stem or branch, and the 
situations in which the trees ordinarily grow; the 
object being to give the whole area of leaf-surface 
full opportunity to obtain all the carbonic acid gas 
possible from the atmosphere, and to get all the avail- 
able sunshine in order that the chlorophyll, or green 
colouring matter of the leaf, may act, which it can 
only do in sunlight. The carbonic acid gas is a 
compound of carbon and oxygen, and it enters the 
leaf through the many breathing pores (stomata). 
When it comes in contact with the chlorophyll this 
seizes hold of the carbon and sets the oxygen free. 
The tree is largely built up of carbon, in combination 
with mineral substances absorbed by the roots, so that 
it is of vital importance that the plant or tree should 
get as much leaf-surface as possible exposed to air 
and sunlight. If you will take a branch from any 
tree and hold it in just the position it had upon the 
