According to Oregon State's Department of Horticulture, leaves are a common way of identifying plants. Leaves may be broad or narrow, simple or compound, and lobed or toothed. It is important, however, to note one of the broader details: a leaf's overall shape.
This leaf has a very narrow shape with almost parallel sides. It comes to a point at the end. This group includes sword-shaped leaves (long and needle-shaped). Most grass blades are linear shaped. A linear leaf can be simple; that is, undivided with only one main section.
This type of blade is similar to the linear leaf but is wider in the center. It is still longer than it is broad and tapers to a point at the end. Most lanceolate leaves are compound leaves and are divided by a septum in the center. Alpinia evergreens have lanceolate leaves, as do daffodils.
This leaf shape is as long as it is broad, with curved sides that are parallel. Certain varieties of mistletoe have oblong leaves, as do nightshade, dumbcane and the Mexican bird of paradise.
This blade takes on the shape of an ellipse. It is wider at the center, and both its ends taper in. The common calathea eclipse plant has this shape of blade.
A plant with ovate leaves has egg-shaped leaves that are broader at the base than at the tip. Magnolias tend to have ovate shaped leaf blades, depending on their variety. Hackberries also have ovate leaves.
A cordate is so named for its heart-shaped blade. The point of the heart may originate at the top or bottom of the leaf. The flowering perennial, cyclamen, has this type of leaf.
The reinform leaf is shaped like a kidney. The English water plant, frog-bit boasts this shape of blade. The Maestro lavender blue geranium also has reinform leaves.
These leaves are shaped like a spatula or spoon. The carnivorous plant Drosera intermedia is one of many with this type of leaf.
As the name implies, these leaves are completely round. Myam Asian Maple trees have orbicular blades. This green, round leaf is used to represent the Major and Lt. Colonel ranks in the military.