ascus

American  

[as-kuhs] / ˈæs kəs /

noun

Mycology.

plural

asci

1. the sac in ascomycetes in which the sexual spores are formed.

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ascus British  

/ ˈæskəs /

noun

1. a saclike structure that produces (usually) eight ascospores during sexual reproduction in ascomycetous fungi such as yeasts and mildews

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ascus Scientific  

/ ăs′kəs /

plural

asci

1. 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.

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Etymology

Origin of ascus

1820–30; < New Latin < Greek askós bag, sac

Example Sentences

The zygote undergoes meiosis without cell division, resulting in an ascus with four 1n nuclei arranged in a row.

From Textbooks • Jan. 1, 2015

A dikaryotic ascus that forms in the ascocarp undergoes plasmogamy, meiosis, and mitosis to form eight ascospores.

From Textbooks • Jan. 1, 2015

A dikaryotic ascus that forms in the ascocarp undergoes karyogamy, meiosis, and mitosis to form eight ascospores.

From Textbooks • Jan. 1, 2015

You can count the eight ascospores in this ascus: The tasty, tasty asci of a Morchella sp.

From Scientific American • Sep. 5, 2012

The number of sporidia contained in an individual ascus is usually less than in the majority of the Ascomycetes, and the sporidia approximate more nearly to the globose form.

From Fungi: Their Nature and Uses by Cooke, M. C. (Mordecai Cubitt)