''Polysiphonia fibrata'' is a species of '' Polysiphonia'' that grows as small dense tufted and finely branched marine alga in the

Rhodophyta Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

Description

The branches of ''P. fibrate'' are numerous and much interwoven forming tufts up to 20 cm long. They are fine, terete, cylindrical, erect and dull brownish-red in colour. The branches consist of a central axis with 4 pericentral cells all of the same length as the axial cells. The branches become corticated near the base. Rhizoids and trichoblasts are abundant.Maggs, C.A. and Hommersand, M.H. 1993. ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales'' The Natural History Museum, London

Reproduction

The plants are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproductio ...

. Spermatangia are borne near the tips of the branches. The cystocarps are clearly shortly stalked. Tetrasporangia are formed in the branches near the tips.

Habitat

To be found on rock, limpets, mussels and on other algae in rock pools at mid-tide and low water.

Distribution

Common around Britain including

Shetland Shetland, also called the Shetland Islands and formerly Zetland, is a subarctic archipelago in Scotland lying between Orkney, the Faroe Islands and Norway. It is the northernmost region of the United Kingdom. The islands lie about to the no ...

and Ireland.Morton, O. 2003. The marine macroalgae of County Donegal, Ireland. ''Bulletin of the Irish Biogeographical Society.'' 27: p.85)Hardy, F.G. and Guiry, M.D. 2003. ''A Check-list and Atlas of the Seaweeds of Britain and Ireland.'' The British Phycological Society Also recorded from Spain, and France.

Note

Other species are similar to ''P. fibrata'' and difficult to distinguish.

References

Rhodomelaceae {{rhodophyta-stub