ascus

[as-kuhs]

noun

Mycology.

plural

asci 

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

ascus

/ ˈæskəs /

noun

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

ascus

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.

Word History and Origins

Origin of ascus¹

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

Word History and Origins

Origin of ascus¹

C19: from New Latin, from Greek askos bag

Example Sentences

Many ascomycetes produce their asci in cups, and in the case of the beech orange, the cups are the orange dimples of the golf ball.

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That is, inside the ascus, a diploid fungal nucleus undergoes meiosis — or sexual, reductive cell division — to produce ascospores.

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The conclusion of the epitaph is perplexing: it states that her husband dedicated it to her and her son's memory—under "the axe"—"Sub asci� dedicavit."

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Ascomycetes.—This, except in the case of a few of the simpler forms, is a very sharply marked group characterized by a special type of sporangium, the ascus.

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Exoascine�, a family of parasitic ascomycetous Fungi, distinguished by the absence of any definite fruit-body, the asci being produced in a layer on the surface of the host.

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