ascus

[ as-kuhs ]

noun

, Mycology.

, plural as·ci [as, -ahy, -kahy, -kee].

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

/ ăs′kəs /

, Plural asci ăs′ī′,-kī′

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

The yellow spores are very minute, each ascus containing eight of them, and they are divided by a transverse partition or septum.

From Project Gutenberg

This operculum may be the more readily seen when the ascus is coloured by a drop of tincture of iodine.

From Project Gutenberg

Each ascus contains a definite number of sporidia, which are sometimes coloured.

From Project Gutenberg

The sporidia are usually eight in each ascus, either arranged in single or double rows, or irregularly grouped together.

From Project Gutenberg

Other species contain linear sporidia, which are often the length of the ascus, and may either be simple or septate.

From Project Gutenberg