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Meaning of protonema

pro•to•ne•ma

Pronunciation: (prō"tu-nē'mu), [key]
— pl. -ma•ta
  1. 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.