Chondrus

genus of red algae

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Last updated

June 24, 2026

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The genus Chondrus refers to a type of red algae, commonly known as Irish moss. This seaweed thrives along the rocky Atlantic coasts of Europe and North America. Its primary component is carrageenan, a gelatinous substance extracted by boiling, which has various industrial applications.1

Irish moss is a tufted seaweed with branching, fan-like fronds that can range from 5 to 25 cm in length. Its color varies from greenish-yellow to dark purple, and when dried, it becomes translucent and horn-like. This alga exhibits an alternation-of-generations life cycle, involving both sexual and asexual stages. Some species of Chondrus are also consumed or used as a gelatin substitute.12

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seaweed
Various species of Chondrus, including Irish moss (C. crispus), carpet the lower half of the zone exposed at low tide along rocky coasts of the Atlantic.
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Various species of Chondrus, including Irish moss (C. crispus), carpet the lower half of the zone exposed at low tide along rocky coasts of the Atlantic.
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