Pronunciation: (prō"tu-nē'mu), [key]
—pl. -ma•taPronunciation: (-mu-tu). [key] Bot.
a primary, usually filamentous structure produced by the germination of the spore in mosses and certain related plants, and from which the leafy plant which bears the sexual organs arises as a lateral or terminal shoot.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.