The midrib is the largest, central vein, becoming the
petiole below the blade. Main veins branch from the midrib
into a successively smaller network.
venation shows all main veins branching from along midrib.
venation shows several main veins branching from a common
point of midrib at base of blade.
venation is essentially pinnate, but main veins curve to follow
margin of blade.
(in many monocots) shows many straight veins side by side from
base to tip.
Leaf surfaces can be smooth and hairless (glabrous), or hairy
in some way. See discussion
on general features.
leaf surfaces can be
or glossy (shiny),
dull (green but not shiny), or
glaucous (pale or whitened).
leaves are thick, stiff, or leathery.
If they persist
beyond Autumn and Winter seasons and fall after new leaves emerge
in Spring they are evergreen. Deciduous
leaves fall before or during the Autumn season. Some leaves may
be tardily deciduous (semi-evergreen); these fall gradually
during Winter, or only after sufficiently cold weather.