Lessoniaceae

Lessoniaceae is a family of brown algae (Phaeophyceae) within the order Laminariales. The family comprises several genera of large kelp-like seaweeds, including Lessonia and Egregia, and its members inhabit temperate to cold marine waters worldwide. They commonly form subtidal canopies on rocky coasts and contribute to coastal ecosystem structure.

Morphology and life cycle: Species in Lessoniaceae typically have a large, leathery thallus with a holdfast, a stipe, and one or more blades that may be simple or highly branched. Some species display feather-like fronds. Reproduction occurs through alternation of generations, with a macroscopic diploid sporophyte producing meiospores within conceptacles borne on receptacles along the thallus.

Ecology and human use: As canopy-forming seaweeds, Lessoniaceae generate complex habitats that shelter a diversity of invertebrates and small fishes and influence local hydrodynamics and sediment processes. Many species are harvested for commercial alginates used as gelling and thickening agents, and some are gathered locally for food in various cultures.

Taxonomy: The circumscription of Lessoniaceae has been refined with molecular data, leading to changes in genera assignment and relationships within the Laminariales. The family remains one of the major contributors to kelp forest diversity in temperate marine environments.

See also: kelp forests, brown algae, Laminariales, Phaeophyceae.