Botany – Compound Leaves

When is a leaf not a leaf?  When it is a compound leaf.  The impulse for this post is I have been harvesting horse chestnuts.

As a professional member of the Ontario Herbalists Association I am responsible for completing annually a certain number of hours in continuing education.  Each year this requirement confounds me.  I feel my whole life is continuing education.  Currently my focus is on improving my skills in botany.

Horse chestnut leaf (Aesculus hippocastanum)

This is a palmately compound leaf.  This is a single leaf made up of several leaflets.  A palmately compound leaf has all its leaflets radiating from a single point at the end of the petiole.  Imagine the palm of the hand and the fingers branching from it. Botany is the common language of plants. Recognizing leaf shapes and understanding how to describe them botanically helps us identify plants we may not know.  I have a soft spot for horse chestnut and love the trees majestic spires of blossoms in the spring.

Elder (Sambucus canadensis)

A compound leaf can also be pinnately compound. Elder is an example of a plant with pinnately compound leaves.  The leaflets all are attached to an extension of the petiole called the rachis.  There is an even number of leaflets with or without a single leaf at the tip of the petiole.

I plan on writing more about how I work with horse chestnut.  Until I do here is some info from the British Herbal Medicine Association.