''Dilsea carnosa'', commonly known as the poor man's weather glass or the sea belt, is a species of

red algae 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 ...

in the

Dumontiaceae Dumontiaceae is a red alga family in the order Gigartinales. Species in the British Isles, includes '' Dumontia contorta'' (S.G.Gmelin) Ruprecht.Irvine, L.M..1983. ''Seaweeds of the British Isles''. Volume 1 Rhodophyta. Part 2A. British Museum. ...

family of the order

Gigartinales Gigartinales is a red algae order in the class Florideophyceae Florideophyceae is a class of red algae. They were once thought to be the only algae to bear pit connections, but these have since been found in the filamentous stage of the Bang ...

Taxonomy

The species was first described scientifically by Schmidel in 1794, under the name ''Fucus carnosus''. The German botanist

Otto Kuntze Carl Ernst Otto Kuntze (23 June 1843 – 27 January 1907) was a German botanist. Biography Otto Kuntze was born in Leipzig. An apothecary in his early career, he published an essay entitled ''Pocket Fauna of Leipzig''. Between 1863 and 1866 he ...

transferred the species to '' Dilsea'' in 1898.

Description

This large alga is dark red, flattened and somewhat leathery. It may be 30 cm or more long and 15 cm wide. It is usually not branched but may split. It grows from a small discoid base.Bunker, F.StP. D., Brodie, J.A., Maggs, C.A. and Bunker, Anne R. 2017. ''Seaweeds of Britain and Ireland.'' Second Edition, Wild Nature Press, Plymouth, UK. The mature blade has a compact medulla enclosed within a cortex of rounded cells inwards and outwards of close radial filaments of about 6 cells.Irvine, L.M.1983. ''Seaweeds of the British Isles''. Volume 1, Rhodophyta Part 2A. British Museum (Natural History) It grows from a discoid holdfast with a short stipe.

Habitat

Attached to rock in the lower littoral, to a depth of 24 m or more. It grows from a discoid holdfast with a short stipe.

Reproduction

The gametangial plants are dioecious, with male and female gametangia on separate plants. The spermatangia, male gametes, occur in patches near the edges of the fronds.

Carposporangia A carpospore is a diploid spore produced by red algae. After fertilization, the alga's carpogonium subdivides into carpospores, and generally the largest type of spore (larger than bispores, which are larger again than tetraspores Tetraspores are ...

release spores. Tetraspores occur near the margins and consist of four spores.

Distribution

Generally distributed around the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles, ...

including the

Shetland Isles 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 ...

and

Isle of Man ) , anthem = "O Land of Our Birth" , image = Isle of Man by Sentinel-2.jpg , image_map = Europe-Isle_of_Man.svg , mapsize = , map_alt = Location of the Isle of Man in Europe , map_caption = Location of the Isle of Man (green) in Europe ...

; from

Portugal Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...

to Arctic Russia.Hardy, F.G and Guiry, M.D. 2003. ''A Check-list and Atlas of the Seaweeds of Britain and Ireland''. British Phycological Society.

References

{{Taxonbar, from=Q5277048 Dumontiaceae Plants described in 1794