''Polysiphonia fibrillosa'' (Dillwyn) Sprengel is a species of marine

red alga Red algae, or Rhodophyta (, ; ), make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest Phylum, phyla of algae, containing over 7,000 recognized species within over 900 Genus, genera amidst ongoing taxon ...

in the

Rhodophyta Red algae, or Rhodophyta (, ; ), make up one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 recognized species within over 900 genera amidst ongoing taxonomic revisions. ...

Description

''Polysiphonia fibrillose'' is a fine red alga which grows to 25 cm long. The erect cylindrical branches are themselves branched and are attached by a discoid holdfast. The branches consist of a central axis of cells each surrounded by 4 (or 5) pericentral cells of equal length and all elongate and of the same length. Corticating filaments grow down in the grooves between the pericentral cells. Rhizoids grow from the pericentral cells. Trichoblasts are numerous.Maggs, C.A. and Hommersand, M.H. 1993. ''Seaweeds of the British Isles''. Volume 1 Rhodophyta Part 3A. The Natural History Museum, London. Other similar species include: ''P. rhunensis'' Thuret et Bornet, ''P.orthocarpa'' Rosenvinge. ''P.sertularioides'' and ''P.sanguinea'' C.Agardh.

Reproduction

The plants are dioecious and bear spermatangia near the apices of the branches. Cystocarps are ovoid or globular and tetrasporangia are formed in series near the apices.

Habitat

Common on rocky shores both in the littoral to the sublittoral 10 m or more. Also grows epiphytically,Hardy, F.G. and Guiry, M.D. 2003. ''A Check-list and Atlas of the Seaweeds of Britain and Ireland.'' British Phycological Society.

Distribution

The species is widespread around

Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...

, including

Shetland Shetland (until 1975 spelled Zetland), also called the Shetland Islands, is an archipelago in Scotland lying between Orkney, the Faroe Islands, and Norway, marking the northernmost region of the United Kingdom. The islands lie about to the ...

, and

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. In Europe it is recorded from

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

, the Baltic and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

References

Rhodomelaceae {{rhodophyta-stub