Palmaria palmata, also called dulse, dillisk or dilsk (from Irish/Scottish Gaelicduileasc/duileasg), red dulse, sea lettuce flakes, or creathnach, is a red alga (Rhodophyta) previously referred to as Rhodymenia palmata. It grows on the northern coasts of the Atlantic and Pacific Oceans. It is a well-known snack food. In Iceland, where it is known as söl[ˈsœːl̥], it has been an important source of dietary fiber throughout the centuries.
The earliest record of this species is on the island of Iona, Scotland where Christian monks harvested it over 1,400 years ago.[2]
Description
The erect frond of dulse grows attached by its discoid holdfast and a short inconspicuous stipe epiphytically on to the stipe of Laminaria or to rocks. The fronds are variable in shape and colour from deep rose to reddish purple and are rather leathery in texture. The flat foliose blade gradually expands and divides into broad segments ranging in size to 50 centimetres (20in) long and 3–8cm (1.2–3.1in) in width which can bear flat, wedge-shaped proliferations from the edge.[3][4] The blade consists of an outer cortex of small cells enclosing a medulla of larger cells up to 0.35 thick.[5][6]
The reference to Rhodymenia palmata var. mollis in Abbott and Hollenberg (1976),[7] is now considered to refer to a different species: Palmaria mollis (Setchel et Gardner) van der Meer et Bird.[8][9]
Dulse is similar to another seaweed, Dilsea carnosa,[10] but Dilsea is more leathery with blades up to 30cm (12in) long and 20cm (7.9in) wide. Unlike P. palmata, it is not branched and does not have proliferations or branches from the edge of the frond, although the older blades may split.[11]
The full haplodiploid life history was not fully explained until 1980.[12] There are two phases in the life-history, with a haploid phase that is dioecious, with separate male and female plants. The large haploid plants are male, having sporangia. Spermatial sori occur scattered over most of the frond of the haploid male plant. The male plants are blade-like and produce spermatia which fertilize the carpogonia of the female crust. The female gametophyte is very small stunted or encrusted, the carpogonia, the female nucleus, apparently occurring as single cells in the young plants. The female plants are minute, less than 1mm), and after fertilization become overgrown by the resulting diploid plant.[13]Tetraspores occur in scattered patches sori (spores) on the mature diploid blade. The adult tetrasporophyte produces tetraspores meiotically in fours.[3][14]
Ecology
P. palmata is to be found growing from mid-tide of the intertidal zone (the area between the high tide and low tide) to depths of 20m or more in sheltered and exposed shores.[14]
Culinary use
Dulse
Dulse is commonly used as food and medicine in Ireland,[15] Iceland, Atlantic Canada, and the Northeastern United States. It can be found in many health food stores or fish markets and can be ordered directly from local distributors. It is also used as fodder for animals in some countries.
It is commonly found from June to September and can be picked by hand when the tide is out. When picked, small snails, shell pieces, and other small particles can be washed or shaken off the plant, which is then spread to dry. Some gatherers may turn it once and roll it into large bales to be packaged later.
Fresh dulse can be eaten directly off the rocks before sun-drying. Sun-dried dulse is eaten as is or is ground to flakes or a powder. When used in cooking, dulse's properties are similar to those of a flavour-enhancer. In Iceland, the tradition is to eat it with butter.[citation needed]. It can be pan-fried quickly into chips, baked in the oven covered with cheese, with salsa, or simply microwaved briefly. It can be used in soups, chowders, sandwiches, and salads, or added to bread or pizza dough. Finely diced, it can be used as a flavour enhancer in meat dishes, such as chili, in place of monosodium glutamate.
In Ireland dulse can be used to make "White Soda Bread".[16] In Ballycastle, Northern Ireland, it is traditionally sold at the Ould Lammas Fair. It is particularly popular along the Causeway Coast. Although a fast-dying tradition,[citation needed] many gather their own dulse. Along the Ulster coastline from County Down to County Donegal, it is eaten dried and uncooked as a snack. It is commonly referred to as dillisk on the west coast of Ireland. Dillisk is usually dried and sold as a snack food from stalls in seaside towns by periwinkle sellers.
P. palmata is the only species of Palmaria found on the coast of AtlanticEurope. It can be found from Portugal to the Baltic coasts and on the coasts of Iceland and the Faroe Islands.[19] It also grows on the shores of Arctic Russia, Arctic Canada, Atlantic Canada, Alaska, Japan, and Korea.[14] Records of P.palmaria from California are actually of Palmaria mollis.[9]
Parasites and diseases
Galls, possibly produced by parasitic nematodes, copepods, or bacteria, are known to infect these plants. They were recorded as "outgrowths of tissue produced by the presence...of an animal."[14][20]
Related Research Articles
Pelvetia canaliculata, the channelled wrack, 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. 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.
Ceramium is a genus of Ceramium algae. It is a large genus with at least 15 species in the British Isles.
Schmitzia hiscockiana is a small, rare, red seaweed or marine alga of the phylum Rhodophyta or red algae. It was discovered and named in 1985.
Polysiphonia is a genus of filamentous red algae with about 19 species on the coasts of the British Isles and about 200 species worldwide, including Crete in Greece, Antarctica and Greenland. Its members are known by a number of common names. It is in the order Ceramiales and family Rhodomelaceae.
Red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity.
Osmundea pinnatifida is a species of red alga known by the common name pepper dulse.
Fucus distichus or rockweed is a species of brown alga in the family Fucaceae to be found in the intertidal zones of rocky seashores in the Northern Hemisphere, mostly in rock pools.
Dilsea carnosa, commonly known as the poor man's weather glass or the sea belt, is a species of red algae in the Dumontiaceae family of the order Gigartinales.
Cordylecladia erecta is a species of red algae in the family Rhodymeniaceae. It is found in the north east Atlantic Ocean and the Mediterranean Sea and is the type species of the genus.
Dumontia contorta is a relatively small epiphytic algae of the sea-shore.
Polysiphonia denudata is a small red alga, Rhodophyta, growing as tufts up to 20 cm long without a main branch axis.
Polysiphonia stricta is a small red marine alga in the Division Rhodophyta.
Hypoglossum hypoglossoides, known as under tongue weed, is a small red marine alga in the family Delesseriaceae.
Phycodrys rubens is a red marine alga of up to 30 cm long.
Phyllophora crispa is a medium-sized fleshy, marine red alga. This alga forms dense mats of up to 15 cm thickness, which influence environmental factors, thus creating habitat for several associated organisms.
Phyllophora pseudoceranoides, the stalked leaf bearer, is a small marine red alga.
Palmaria is a genus of algae. One of its most notable members is dulse, Palmaria palmata.
Palmariaceae is a family of algae. It includes the edible seaweed dulse.
Prasiola stipitata is a small green alga.
Gymnogongrus griffithsiae is a small uncommon seaweed.
1 2 Indergaard, M. and Minsaas, J. 1991. 2 "Animal and human nutrition." in Guiry, M.D. and Blunden, G. 1991. Seaweed Resources in Europe: Uses and Potential. John Wiley & Sons. ISBN0-471-92947-6
↑ Hiscock, S. 1986. A Field Key to the British Red Seaweeds. Occasional Publications No. 13. Field Studies Council, Dorset Press, Dorchester ISBN1-85153-813-5.
↑ John P. van der Meer & Edna R. Todd (1980). "The life history of Palmaria palmata in culture. A new type for the Rhodophyta". Canadian Journal of Botany. 58 (11): 1250–1256. doi:10.1139/b80-155.
↑ 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 ISBN978-0-9955673-3-7
1 2 3 4 Irvine, L.M. & Guiry, M.D. "Palmariales and Rhodymeniales" in Irvine, L.M. 1983. Seaweeds of the British Isles. Volume 1. Part 2A. Cryptonemiales (sensu stricto) Palamriales, Rhodymeniales. British Museum (Natural History), London. ISBN0-565-00871-4
Grubb, V.M. 1923. Preliminary note on the reproduction of Rhodymenia palmata, Ag. Annals of Botany37: 151–52.
Pueschel, C.M. 1979. Ultrastructure of the tetrasporogenesis in Palmaria palmata (Rhodophyta). Journal of Phycology15: 409–424.
South, G.R. and Hooper, R.G. 1980. A Catalogue and Atlas of the Benthic Marine Algae of the Island of Newfoundland. pp.1–136. Memorial University of Newfoundland Occasional Papers in Biology.
Lennon, B.W. and Doyle, E. Wild Food. The O'Brien Press, Dublin. ISBN978-1-84717-467-3
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
