Rhizoma

Part of speech: noun

Definitions

1. A subterranean stem that generates roots and shoots while supporting vegetative reproduction
2. An underground organ that stores nutrients and enables certain plants to reproduce asexually
3. A stem beneath the soil surface that allows a plant to grow new shoots and roots for reproduction ; a part of a plant underground that acts as a reservoir for storing essential nutrients

Etymology: "Rhizoma" is a New Latin borrowing from the Greek "rhizōma", meaning "mass of roots" or "a root-like growth", itself formed from "rhiza", "root". Greek writers used the word for things like the root stock of a plant, and the Latin-based botanical term carried that sense into scientific writing. Its English use is largely confined to botany, where it is a technical term rather than everyday vocabulary. The sense is also a good example of how botanists have sharpened a term over time. Ancient authors used "rhizōma" loosely for roots and root-like masses, but modern botany distinguishes the rhizome from a true root: it is a stem that grows horizontally underground, bears nodes and scale leaves, and sends up shoots while also putting down roots from its lower surface. Ginger, iris and couch grass are familiar examples, which is why a single plant can spread across a patch of ground without any seeds.