Leaves are categorized depending on their shapes, whether they are stalked or not, and if the leaves have smooth or jagged edges. All leaves are divided into two main types: simple or compound.
A simple leaf is one that stands on its own, such as a maple leaf. It has one petiole, or stalk, connecting it to the plant stem. Sessile leaves, those that do not have a stalk, fall into this category. Corn has sessile leaves.
A compound leaf is made up of distinct leaflets, such as those found on heather plants. A large petiole runs down the middle, with the individual leaflets attached to the main stalk by their smaller petioles.
Elliptic leaves are like an expanded oval, with the length at least twice as long as the width. Lanceolate leaves are spear-shaped with a wider base that tapers to a point. Acicular leaves are needle-shaped, such as the leaves on pine and fir trees. Ovate leaves resemble an egg with a wider base that is divided by the petiole. Cordate leaves are similar, but more heart-shaped.
Maple leaves are hastate leaves. They are wider at the bottom and have separate sections, called lobes, branching out and ending in pointed tips. Linear leaves, like on the corn, are long and thin. Edges on leaves can be smooth, curvy or lobed, with an undulating edge.
Two types of leaves, dentate and serrate, have jagged edges.