What Are the Different Kinds of Leaves?

It is best to look at the different kinds of leaves in terms of categories, since that is how they are defined. However, for a quick view, here are some of the different kinds of leaves:

Simple leaves
Compound leaves
Petiole stemmed
Sessile stemmed
Ovate
Cordate
Lanceolate
Elliptic
Hastate
Acicular
Linear
Lobed
Dentate
Serrate
Sinuate
Smooth edges/entire edges

Categories of Leaves

Leaves are categorized by:

Complexity
Stem
Shape
Edge

Complexity

Simple leaves are those which the leaves go outward, and they are all in a unified shape. You will see a central artery straight up in the leaf, and you will see veins coming out from it.

In compound leaves, you will notice that they appear to be like multiple leaves that have been combined together. The central artery separates and goes off into various paths. The leaf will look like it has more than one leaf attached to it. However, they are really all part of just one leaf, and those leaf-like appendages are called leaflets.

Stem

Leaves are categorized as having one of two different types of stems...or lack thereof, rather.

Leaves with stems on them are known as petiolated. The name comes f rom the fact that stems are actually known as petioles in the scientific community. However, not all of the leaves fall off of trees with stems attached to them.

If a leaf does not have a stem on it, then are known as sessiles. When we are talking about sessiles, we are talking about leaves that are directly connected to the branches.

Shape

Leaves come in various distinctive shapes:

Ovate leaves look as they sound that they should. These leaves are shaped like eggs, and they have sharp, pointed ends.
The cordate leaves are another one where the name directly relates to the shape. If you did not know, "cordate" is the Latin word for "heart." Therefore, cordate leaves are shaped like hearts. They are wider at the base than the ovate leaves.
Another leaf shape is the lanceolate. These leaves tend to look like lances. Lances are another word for spears. They look like cordate leaves, except they are not as wide at the base.
Elliptic leaves are kind of a type of ovate leave; they are just much thinner than their egg shaped cousin.
Hastate leaves are a type of complex leaf. These varieties are comprised of three connected leaves which stretch out from one main point.
Acicular leaves are often found on pine trees. They are long, needle-like, and have pointed tips.
Linear leaves are like acicular leaves, except they have rounded ends.

Edge

Lobed leaves have lobes on them that point out at random intervals.
Dentate leaves, which come from the Latin word for "teeth," have little teeth-like markings along the edges of them.
Serrate leaves are similar to dentate leaves, except the little teeth are much closer together than on a dentate.
Sinuate leaves have curved edges with waves and/or bumps along the sides.
Leaves with edges known as "entire edges" are generally those that have smooth edges.

Now you know a wealth of information about the different kinds of leaves, and you are probably just about ready to get out there and start identifying some leaves on your own!