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[meg-uh-spawr, -spohr] /ˈmɛg əˌspɔr, -ˌspoʊr/
noun, Botany
the larger of the two kinds of spores characteristically produced by seed plants and a few fern allies, developing into a female gametophyte.
Compare microspore.
the embryo sac of a flowering plant.
Also called macrospore.
Origin of megaspore
1885-90; mega- + spore
Related forms
[meg-uh-spawr-ik, -spor-] /ˌmɛg əˈspɔr ɪk, -ˈspɒr-/ (Show IPA),
adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for megaspores
Historical Examples
  • The germination of the megaspores is started in the sporangium; at a certain point in their development they are shed.

    How to Know the Ferns S. Leonard Bastin
  • The number of microspores produced is very large, but only four megaspores are borne in each megasporangium.

    How to Know the Ferns S. Leonard Bastin
  • The megaspores are, of course, very much larger than the microspores.

    How to Know the Ferns S. Leonard Bastin
  • The megaspores bear hooks, and in this way the two processes become attached.

    How to Know the Ferns S. Leonard Bastin
British Dictionary definitions for megaspores


Also called macrospore. the larger of the two types of spore produced by some spore-bearing plants, which develops into the female gametophyte Compare microspore (sense 1)
the cell in flowering plants that gives rise to the embryo sac
Derived Forms
megasporic, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for megaspores



1857, from mega- + spore.

Online Etymology Dictionary, © 2010 Douglas Harper
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megaspores in Science
One of the two types of haploid spores produced by a heterosporous plant. Megaspores develop into female gametophytes and are usually larger than microspores.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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