megaspore

American  

[meg-uh-spawr, -spohr] / ˈmɛg əˌspɔr, -ˌspoʊr /

noun

Botany.

1. the larger of the two kinds of spores characteristically produced by seed plants and a few fern allies, developing into a female gametophyte.

2. the embryo sac of a flowering plant.

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megaspore British  

/ ˈmɛɡəˌspɔː /

noun

1. 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

2. the cell in flowering plants that gives rise to the embryo sac

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megaspore Scientific  

/ mĕg′ə-spôr /

1. One of the two types of haploid spores produced by a heterosporous plant. Megaspores develop into female gametophytes and are usually larger than microspores.

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Other Word Forms

• megasporic
  adjective

Etymology

Origin of megaspore

First recorded in 1885–90; mega- + spore

Example Sentences

The megaspore mother cell divides by meiosis to produce four haploid megaspores.

From Textbooks • Jan. 1, 2015

A megaspore develops into a female gametophyte containing a haploid egg.

From Textbooks • Jan. 1, 2015

Only the large megaspore survives; it produces the female gametophyte, referred to as the embryo sac.

From Textbooks • Jan. 1, 2015

During the second phase, megagametogenesis, the surviving haploid megaspore undergoes mitosis to produce an eight-nucleate, seven-cell female gametophyte, also known as the megagametophyte or embryo sac.

From Textbooks • Jan. 1, 2015

For an account of the further development of the megaspore, and the formation of the egg-cell, from which after fertilization is formed the embryo, see Gymnosperms and Angiosperms.

From Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 5 "Fleury, Claude" to "Foraker" by Various