Interpinnate

Interpinnate is a term used in botany to describe a type of compound leaf. In an interpinnate leaf, the leaflets are arranged in a pinnate fashion, meaning they are attached to a central rachis. However, the key characteristic of interpinnate leaves is that the leaflets are not directly opposite each other on the rachis. Instead, they are staggered or alternate in their placement. This arrangement differs from a truly pinnately compound leaf where leaflets are typically arranged in pairs directly across from each other.

The term interpinnate suggests an intermediate or partially pinnate structure. While the leaflets are attached to a central axis like in a pinnate leaf, their alternating pattern gives them a slightly different appearance. This arrangement can be seen in certain plant species, contributing to the diversity of leaf morphology in the plant kingdom. Understanding leaf arrangement, including terms like interpinnate, is important for plant identification and classification. Botanists use these precise terms to describe the intricate structures of leaves and their evolutionary relationships. The specific arrangement of leaflets on the rachis can be a distinguishing feature for identifying different plant genera and species.