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Leaves
vary greatly from plant to plant and are useful in
classification and
identification. Some leaves also store food and water, provide support,
or form new plants. Where high light intensities are harmful, leaves may
reduce the effects of the light by orientating themselves vertically; by
becoming thickened or covered with hairs or
wax or by having a highly
reflective surface.
 Leaf
Parts: Any of these parts may be lacking,
modificate or reduced. Lamina:
The expanded portion or blade of a leaf.
Leaf apex:
The tip of a leaf opposite to the petiole
Midrib
The the central vein of a leaf
it is usually continuous with the petiole.
Vein: The
vascular structures on a leaf
which arrangement is called venation.
Petiole:
The stalk or stem that connects the leaf to the plant, frequently
with a basal enlargement called
pulvinus (petiole are
absent in sessile leaves)
Axil: The
angle between the upper side of the stem and a leaf or petiole
Stem
(also called the axis) from which the
leaves arise.
Stipule:
The pair of small, appendages one on each side at the
base of the petiole.
The forms of leaves lamina vary greatly
from plant to plant and are useful in classification and identification.
See:
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