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

brown alga Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and p ...

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

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

. 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 "unispec ...

''Pelvetia''. In 1999, the other members of this genus were reclassified as ''

Silvetia ''Silvetia'' is a genus of brown algae, commonly known as rockweed, found in the intertidal zone of rocky seashores of the Pacific Ocean. These were originally classified as members of the genus ''Pelvetia''. In 1999, ''Silvetia sp.'' was created ...

'' due to differences of

oogonium An oogonium (plural 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 l ...

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 and mucous cells. It ...

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

cryptostoma Cryptostomata (singular: cryptostoma) are structures found in some types of brown algae. The anatomical structures are found in some species of '' Fucus'', but not in '' Pelvetia canaliculata''. They are conceptacle Conceptacles are specialized ca ...

ta. 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

conceptacle Conceptacles are specialized cavities of marine and freshwater algae that contain the reproductive organs. They are situated in the receptacle and open by a small ostiole.Boney, A.D. (1969). ''A Biology of Marine Algae''. Hutchinson Educational Lt ...

s are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have ...

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 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 stu ...

and

Gustave Adolphe Thuret Gustave Adolphe Thuret (23 May 1817 – 10 May 1875) was a noted French botanist, and founder of the Jardin botanique de la Villa Thuret. Biography Born in Paris, he belonged to an old Huguenot family, which had sought refuge in Weesp (Dutch ...

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 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 inundated), to coastal ...

, 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 () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

and other longshore

angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants ...

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 oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

shores of Europe from

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

, including

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of ...

Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...

Great Britain Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It ...

, the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

and

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 th ...

. In Ireland, collection of ''Pelvetia canaliculata'' ( ga, dúlamán) 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 Fucales genera Monotypic brown algae genera Edible algae Fucaceae Taxa named by Joseph Decaisne Taxa described in 1845