- the sac in ascomycetes in which the sexual spores are formed.
Origin of ascus
1820–30; < New Latin < Greek askós bag, sac
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for ascus
In the latter species there are only two spores in an ascus.Studies of American Fungi. Mushrooms, Edible, Poisonous, etc.
George Francis Atkinson
Ascus (asci), a sac, the spore-case of Lichens and some Fungi.The Elements of Botany
By crushing the ripe spore fruit, these spores still enclosed in the mother cell (ascus) may be forced out (Fig. 39, H).Elements of Structural and Systematic Botany
Douglas Houghton Campbell
Sporidia of same inclosed in ascus with accompanying paraphyses.
The term sporidia he limits to spores produced or enclosed in an ascus, as in the Ascomycete.
- a saclike structure that produces (usually) eight ascospores during sexual reproduction in ascomycetous fungi such as yeasts and mildews
C19: from New Latin, from Greek askos bag
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
Word Origin and History for ascus
"sac in certain fungi," 1830, Modern Latin, from Greek askos "leather bag, wine skin," of unknown origin.
Online Etymology Dictionary, © 2010 Douglas Harper
- A membranous, often club-shaped structure in which typically eight spores are formed through sexual reproduction of ascomycetes.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- A membranous, often club-shaped structure inside which ascospores are formed through sexual reproduction in species of the fungi known as ascomycetes. The ascus is unique to ascomycetes and distinguishes them from other kinds of fungi. Asci are formed when two hyphae that are sexually compatible conjugate. Each ascus typically develops eight ascospores. Asci swell at maturity until they burst, shooting the ascospores into the air.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.