Palmaria palmata

''Palmaria palmata'', also called dulse, dillisk or dilsk (from Irish/ Scottish Gaelic '/'), 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 ' , it has been an important source of dietary fiber throughout the centuries.

History

The earliest record of this species is on the island of Iona, Scotland where Christian monks harvested it over 1,400 years ago.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.

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 long and in width which can bear flat, wedge-shaped proliferations from the edge.Hoek, C.van den, Mann, D.G. and Jahns, H.M. 1995.
Algae: An Introduction to Phycology
'. Cambridge University Press, Cambridge. . The blade consists of an outer cortex of small cells enclosing a medulla of larger cells up to 0.35 thick.

The reference to ''Rhodymenia palmata'' var. ''mollis'' in Abbott and Hollenberg (1976),Abbott, I.A. and Hollenberg, G.J. 1976. ''Marine Algae of California.'' Stanford University Press, California. . is now considered to refer to a different species: '' Palmaria mollis'' (Setchel et Gardner) van der Meer et Bird.Mondragon, J. and Mondragon, J. 2003. ''Seaweeds of the Pacific Coast.'' Sea Challengers, California. .

Dulse is similar to another seaweed, '' Dilsea carnosa'', but ''Dilsea'' is more leathery with blades up to long and 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.Hiscock, S. 1986. ''A Field Key to the British Red Seaweeds.'' Occasional Publications No. 13. Field Studies Council, Dorset Press, Dorchester .

Life history

The full life history was not fully explained until 1980. There are two phases in the life-history, that is it is dioecious, male and female plants grow separately. The large plants are male or have sporangia. The female plants are minute, less than 1 mm) and become overgrown after fertilization by the diploid plant.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 Tetraspores occur in scattered patches sori (spores) on the mature blade, diploid blade. Spermatial sori occur scattered over most of the frond of the haploid (single cell) male plant. The female gametophyte is very small stunted or encrusted, the carpogonia, the female nucleus, apparently occurring as single cells in the young plants. The male plants are blade-like and produce spermatia which fertilize the carpogonia of the female crust. The adult tetrasporophyte produces tetraspores meiotically in fours.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.

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 20 m or more in sheltered and exposed shores.

Culinary use

Dulse is commonly used as food and medicine in Ireland, 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.

Dulse is a good source of minerals and vitamins compared with other vegetables, contains all trace elements needed by humans, and has a high protein content. Dulse contains iodine, which prevents goitre.

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.. 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". 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, 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.

Researchers at Oregon State University's Hatfield Marine Science Center have selected a fast-growing strain of Pacific dulse (''P. mollis''). Originally intended as a feed for abalone farming, they claim their strain of the seaweed tastes like bacon when fried.

Distribution

''P. palmata'' is the only species of ''Palmaria'' found on the coast of Atlantic Europe. It can be found from Portugal to the Baltic coasts and on the coasts of Iceland and the Faroe Islands. Børgesen, F. (1903) Marine algæ. In: '' Botany of the Færöes'' Vol. II, pp. 339-532. Copenhagen and London. It also grows on the shores of Arctic Russia, Arctic Canada, Atlantic Canada, Alaska, Japan, and Korea. Records of ''P. palmaria'' from California are actually of ''Palmaria mollis''.

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."

References

Further reading

* Grubb, V.M. 1923. Preliminary note on the reproduction of ''Rhodymenia palmata'', Ag. ''Annals of Botany'' 37: 151–52.
* Pueschel, C.M. 1979. Ultrastructure of the tetrasporogenesis in ''Palmaria palmata'' (Rhodophyta). ''Journal of Phycology'' 15: 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.

External links

AlgaeBase

''Palmaria palmata''
at Michael Guiry's Seaweed Site
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{{Authority control
Cuisine of Atlantic Canada
Icelandic cuisine
Cuisine of Northern Ireland
Irish cuisine
Florideophyceae
Edible seaweeds
Species described in 1753
Edible algae