Common Leaf Structures Explained for Beginners

leaf structure

What is the structure of this leaf?  Photo via Flickr.

Leaf structures are another step in leaf identification for beginners.  Here are the handful of common leaf structures that beginners should become familiar with.

Have you ever been out on a hike with your kids in the Rocky Mountains and wondered what that tree was?  A basic knowledge of how to describe the leaves of a plant is super helpful with being able to identify trees.  One thing that can help with describing leaves is knowing the different leaf structures.  These are fairly simple, but are important to know.

What Is A Leaf?

First, let’s make sure it is clear what a leaf is.  A leaf is a typically flat part of the plant where photosynthesis takes place.

A leaf is made up of two parts – the blade (what we think of as the leaf) and the stalk.  The blade of each leaf is the wide, green part of the leaf.  The stalk is what connects the leaf to the stem of the plant.

What Is the Leaf Structure?

Leaf structures mean the general form or structure of the leaf.  I do not mean the shape of the leaf when you look at it.  That is the leaf shape.  The leaf structure means the overall structure of the leaf itself.

Is it one leaf by itself, no matter the shape, that connects to the stem of the plant or tree?  Or maybe it is more complex and made up of different levels of leaves (compound) that connect to the stem of the plant or tree.

Common Leaf Structures

leaf structures

Photo via Flickr.

Simple – this is just one leaf by itself connecting to the stem.

Compound Forms of Leaf Structures

leaf arrangement

Pinnately Compound.  Photo via Flickr.

Pinnately Compound – In this structure there is a central stalk of each leaf with many smaller leaflets coming off of it.  The central stalk is not woody material, but is part of the leaf itself.  This central stalk of the leaf connects to the woody stem, branch, or twig.  For these types of plants, one leaf consists of the central stalk and the many individual ‘leaflets’.

leaf arrangement

Bipinnately compound.  Photo via Flickr.

Doubly Pinnately Or Bipinnately Compound – This is similar to pinnately compound, but there is one more level to the leaves.  So, there is a central stalk of each leaf, then off of that are many smaller stalks, which each have many tiny leaflets coming off of them.  Then the entire ‘leaf’ connects to a woody stem or twig from the original central stalk.

leaf arrangement

Palmately compound.  Photo via Flickr.

Palmately Compound – This is a compound leaf that is made up of more than 3 leaflets coming off of a central stalk of the leaf.  Notice in the photo above that each of the tiny stems are green and come  from a central point or stalk that then connects to the stem of the plant.