multileaflet

Multileaflet is a botanical term used to describe a leaf that is subdivided into multiple leaflets, all attached to a single petiole. This contrasts with simple leaves, which are single, undivided blades. Leaflets are typically arranged in recognizable patterns and may function together as a single photosynthetic unit.

The term encompasses several architectural patterns of compound leaves. In pinnate leaves, leaflets are arranged along a central axis (rachis) on either side. In bipinnate leaves, the primary divisions themselves bear smaller leaflets. Palmate compounds have leaflets radiating from a common point at the end of the petiole. The unifying feature is the presence of more than one leaflet per leaf.

Examples of multileaflet leaves occur across various plant groups. Horse chestnut (Aesculus hippocastanum) has palmate leaves with several large leaflets. Many trees and shrubs in the walnut family (Juglandaceae) or ash family (Oleaceae) display pinnate leaves with multiple leaflets. Poison ivy (Toxicodendron radicans) is often cited for its trifoliate leaves, a basic form of multileaflet foliage. In cultivated plants, leaf architecture is a common criterion in taxonomy and selection, influencing both identification and breeding.

Function and implications of multileaflet architecture include potential advantages in light capture, wind resilience, and modular growth. Leaflets can vary in size and shape to optimize photosynthesis and reduce damage from environmental stresses. The concept remains a standard descriptive category in botany and horticulture for plants with divided leaves.