from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The larger of two types of spores that give rise to a female gametophyte. Also called macrospore.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The larger spore of a heterosporous plant, typically producing a female gametophyte
from The Century Dictionary and Cyclopedia
- n. Same as macrospore.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. larger of the two types of spore produced in heterosporous plants; develops in ovule into a female gametophyte
This one haploid cell, the megaspore, then undergoes three successive mitoses to form the embryo sac, or the female gametopyhte.
The behaviour of the chromosomes in meiosis or reduction division both in the pollen mother-cells and in the megaspore mother-cells which give rise to the so-called embryo-sac are fully described by Gates.
Female cone develops two ovules on the upper surface of each cone scale; each ovule contains haploid megaspore.
In the ovules of most sexual flowering plants female gametogenesis is initiated from a single surviving gametic cell, the functional megaspore, formed after meiosis of the somatically derived megaspore mother cell (MMC) 1, 2.