OF THE LEAF AND ITS PARTS. 5 
As this stem lengthens, it unfolds what are commonly 
known as leaves, which when the plant is fully grown 
usually form its principal and most permanent beauty : 
they are considered as additions or appendages to the 
stem, as they are thrown off after a certain season, or 
when they have done their work in the plant. The 
stem in the young plant, and in those which do not 
attain any great size or age, is of a green or greenish 
tint; and when the plant grows older this colour 
changes to brown; as may be seen in trees and shrubs, 
in which all the new shoots will be found to be green 
during the first year of their existence, and brown 
during the remainder. 
6. A great difference exists in the forms of the stems 
of plants, for while some are straight and do not divide, 
others are much divided or branched; some stems rise up 
from the ground, while others lie on it; others again 
twine round their neighbours, as in the Convolvulus or 
Bindweed. All these are various kinds of stems, but 
as a general rule, whatever part of a plant is above 
ground, of a greenish or greenish-brown colour, may 
be considered as a stem or belonging to the stem; while 
all below the ground as belonging to the root, which is 
of a lighter colour and never green. 
OF THE LEAF, 
7. All are well acquainted with what is called the 
leaf of a plant; it is generally a flattened, thin, almost 
always green body of variable size and form, situated 
on the stem or branches of a plant. Take for example 
an Apple or Lilac leaf; first, there is a broad thin part 
