''Pelvetia canaliculata'', the channelled wrack, is a very common

brown alga Brown algae (: alga) are a large group of multicellular algae comprising the class Phaeophyceae. They include many seaweeds located in colder waters of the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar reg ...

(Phaeophyceae) found on the rocks of the upper shores of

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. It is the only species remaining in the

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

''Pelvetia''. In 1999, the other members of this genus were reclassified as '' Silvetia'' due to differences of

oogonium An oogonium (: oogonia) is a small diploid cell which, upon maturation, forms a primordial follicle in a female fetus or the female (haploid or diploid) gametangium of certain thallophytes. In the mammalian fetus Oogonia are formed in large ...

structure and of nucleic acid sequences of the rDNA.

Description

''Pelvetia'' grows to a maximum length of in dense tufts, the fronds being deeply channeled on one side: the channels and a

mucus Mucus (, ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both Serous fluid, serous and muc ...

layer help prevent the seaweed drying (desiccation) when the tide is out. It is irregularly dichotomously branched with terminal receptacles, and is dark brown in color. Each branch is of uniform width and without a midrib. The receptacles are forked at the tips. It is distinguished from other large brown algae by the channels along the frond. It has no mid-rib, no air-vesicles and no cryptostomata. It forms the uppermost zone of algae on the shore growing at or above high-water mark. The reproductive organs form swollen, irregularly shaped receptacles at the end of the branches. The conceptacles are

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

and borne within the receptacles at the apices.

Taxonomy

The genus name of ''Pelvetia'' is in honour of François Alexandre Pelvet (1801–1882), who was a French

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

and plant collector. The genus was circumscribed by

Joseph Decaisne Joseph Decaisne (7 March 1807 – 8 January 1882) was a French botanist and agronomist. He became an ''aide-naturaliste'' to Adrien-Henri de Jussieu (1797–1853), who served as the chair of rural botany. It was during this time that he began to ...

and Gustave Adolphe Thuret in ''Ann. Sci. Nat. Bot.'' ser. 3, vol. 3 on page 12 in 1845.

Reproduction

Both sexes occur in the same plant, the reproductive structures develop at the apices. The receptacles are swollen during the summer and are yellowish-green at maturity.

Ecology

''Pelvetia canaliculata'' is the only large algae growing on rocks forming a zone along the upper shore at the upper

littoral zone The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood ...

, on the shores of the British Isles. It tolerates a wide range of exposure conditions. It needs periods of exposure to the air, and sometimes grows so high up a beach that coarse

grass Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family (biology), family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and spe ...

and other longshore

angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit ...

s grow among it. If it is submerged for more than six hours out of 12 it begins to decay.

Distribution

''Pelvetia canaliculata'' is common on the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

shores of Europe from

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, including

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 ...

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 ...

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 ...

, the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

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 ...

and

Portugal Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...

. In Ireland, collection of ''Pelvetia canaliculata'' () has been recorded as a source of sustenance during times of famine. A popular Irish folk song, ', describes events transpiring between two people who collected the seaweed as a profession.

References

External links

* * * {{Taxonbar, from=Q16034789 Fucales genera Monotypic brown algae genera Edible algae Fucaceae Taxa named by Joseph Decaisne Taxa described in 1845