Pinnule

Part of speech: noun

Definitions

1. A diminutive leaf segment or secondary division of a compound leaf is described by this term, which specifically refers to the leaflets in ferns and similar structures in vascular plants
2. This expression denotes the smaller, often ornamental leaflets found in compound leaves, particularly in the context of ferns and other vascular flora
3. A term that identifies the smaller leaflets or subdivisions of a compound leaf, particularly observed in the anatomy of ferns and related plant species

Etymology: "Pinnule" comes from Latin "pinnula," the diminutive of "penna" (feather) or "pinna" (wing, feather). The Latin diminutive suffix "-ula" means "little," so the word literally names a small feather or small wing. The image is apt: the pinnule is a tiny leaflet arranged along a larger frond much as a feather's barbs line its shaft. In botany the term describes the ultimate subdivisions of a compound leaf, most often in ferns, where a pinna (a primary leaflet) is itself divided into smaller units. The sense moved from a feather to a plant part because botanists borrowed the Latin word's imagery of small, winglike parts branching from a central stalk, a pattern that gives many fern fronds their feathery look.

Synonyms: leaflet, frond, INVALID, INVALID, INVALID