Rhachises

Part of speech: noun

Definitions

1. A structure that serves as the central spine or axis of a leaf or fern, providing support and nutrient distribution
2. The main stem of a leaf where smaller leaflets are attached, facilitating growth and stability in plant forms
3. An anatomical term referring to the supporting central stem of various botanical structures, involved in leaf arrangement and function

Etymology: "Rhachises" is the plural of "rhachis," a term for the central stem or axis that bears leaves, leaflets, or flowers, as in a fern frond or the spine of a feather. The singular comes from Greek "rhachis," meaning spine or backbone, and the same Greek root gives English the word "rachis" in the same sense. The Greek plural-forming pattern is what produces the "-es" ending here, so "rhachises" is the form biologists use when they mean more than one such stem.

Synonyms: ridges, spines, backbones