Palm Leaf Structure
Palms are an iconic Florida plant, and there are many species and varieties. As you admire these tropical emblems, have you ever wanted to know the difference between the types of palm leaves?
Palm leaves are generally one of three types; pinnate, palmate, or costapalmate.
Pinnate leaves, which are sometimes described as being feather-like, have leaflets entirely separated from each other that are attached perpendicularly to the rachis. The rachis is an extension of the petiole which extends into the leaf blade. Example of a pinnate-leaved palms are coconut, queen, and date palms.
Palmate leaves, which can be referred to as fan palms, have adjacent leaflets or leaf segments that are joined laterally for some or most of their length. They originate from a single point at the tip of the petiole, which often includes a specialized protuberance called the hastula. Mexican fan palm, windmill palm, and sugar palms are typical palmate-leaved palms.
Costapalmate leaves are intermediate between pinnate and palmate leaves, with the overall leaf blade being round to oval in shape. Leaflets are joined together for some or most of their length but are attached along a costa, which is an extension of the petiole into the leaf blade. Sabal species have costapalmate leaves.
More general palm leaf information
Palm leaflets are typically V shaped in cross section with the midvein at the apex of the V. Palm leaves with upright V-shaped leaflets are called induplicate, while those with an inverted V shape are called reduplicate.
All palm leaves are attached to the trunk by a flared leaf base. In some palms, like royal palms (Roystonea regia), the leaf bases are tubular and wrap around each other, forming a smooth, stem-like structure called a crownshaft.
Next time you’re enjoying the relaxing tropical appeal of a palm, you can impress anyone around with your newly acquired knowledge of palm morphology.
Also on Gardening Solutions
- Not Your Average Palm--Presentation by Christine Kelly-Begazo, UF/IFAS Extension Indian River County (PDF)
- Palm Morphology and Anatomy
An Excellent Resource
- The line drawings and royal palm photograph in this article are from the website Identifying Commonly Cultivated Palms.
Citation: Anderson, P.J. 2011. Identifying Commonly Cultivated Palms. In A Resource for Pests and Diseases of Cultivated Palms. Florida Department of Agriculture and Consumer Service, Division of Plant Industry and Identification Technology Program, CPHST, PPQ, APHIS, USDA; Fort Collins, CO. [February 6, 2019] <http://idtools.org/id/palms/palmid/>