Pelvetia
| Pelvetia | |
|---|---|
| |
| Close-up | |
| File:Pelvetia canaliculata on slipway.jpg | |
| Growing on the side of a slipway | |
| Scientific classification Edit this classification | |
| Domain: | Eukaryota |
| Clade: | Sar |
| Clade: | Stramenopiles |
| Division: | Ochrophyta |
| Class: | Phaeophyceae |
| Order: | Fucales |
| Family: | Fucaceae |
| Genus: | Pelvetia Decne. & Thur. |
| Species: | P. canaliculata
|
| Binomial name | |
| Pelvetia canaliculata | |
| Synonyms [1] | |
| |
Pelvetia canaliculata, the channelled wrack,[2] is a very common brown alga (Phaeophyceae) found on the rocks of the upper shores of Europe. It is the only species remaining in the monotypic genus Pelvetia.[1][3] In 1999, the other members of this genus were reclassified as Silvetia due to differences of oogonium structure and of nucleic acid sequences of the rDNA.[4]
Description
[edit | edit source]Pelvetia grows to a maximum length of 15 centimetres (6 in) in dense tufts, the fronds being deeply channeled on one side: the channels and a mucus layer help prevent the seaweed drying (desiccation) when the tide is out. It is irregularly dichotomously branched[5] with terminal receptacles,[6] 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.[7] The reproductive organs form swollen, irregularly shaped receptacles at the end of the branches. The conceptacles are hermaphrodite and borne within the receptacles at the apices.
Taxonomy
[edit | edit source]The genus name of Pelvetia is in honour of François Alexandre Pelvet (1801–1882), who was a French naturalist and plant collector.[8]
The genus was circumscribed by Joseph Decaisne and Gustave Adolphe Thuret in Ann. Sci. Nat. Bot. ser. 3, vol. 3 on page 12 in 1845.
Reproduction
[edit | edit source]Both sexes occur in the same plant, the reproductive structures develop at the apices.[9] The receptacles are swollen during the summer and are yellowish-green at maturity.[10]
Ecology
[edit | edit source]Pelvetia canaliculata is the only large algae growing on rocks forming a zone along the upper shore at the upper littoral zone, on the shores of the British Isles. It tolerates a wide range of exposure conditions.[11] It needs periods of exposure to the air, and sometimes grows so high up a beach that coarse grass and other longshore angiosperms grow among it. If it is submerged for more than six hours out of 12 it begins to decay.[12]
Distribution
[edit | edit source]Pelvetia canaliculata is common on the Atlantic shores of Europe from Iceland to Spain, including Norway, Ireland, Great Britain, the Netherlands, France and Portugal.[13] In Ireland, collection of Pelvetia canaliculata (Irish: dúlamán) has been recorded as a source of sustenance during times of famine.[14] A popular Irish folk song, Dúlamán, describes events transpiring between two people who collected the seaweed as a profession.[citation needed]
References
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- ^ Bunker, F.StP. D., Brodie, J.A., Maggs, C.A. and Bunker, A.R. 2017 Seaweeds of Britain and Ireland. Second Edition. Wild Nature Press, Plymouth, UK. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Dickinson, C.I. 1963. British Seaweeds. The Kew Series
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External links
[edit | edit source]- Error creating thumbnail: File missing Media related to Lua error in Module:Commons_link at line 62: attempt to index field 'wikibase' (a nil value). at Wikimedia Commons
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