dulse n : coarse edible red seaweed [syn: Rhodymenia palmata]

English

Etymology

From Irish or Gaelic duileasg, cognate with Welsh delysg.

Pronunciation

• /dʌls/

Noun

1. A seaweed of a reddish brown color which is sometimes eaten, as in Scotland.

   • 1997: Then Egil said, ‘That happens if you eat dulse, it makes you even thirstier.’ — ‘Egil's Saga’, tr. Bernard Scudder, The Sagas of Icelanders (Penguin 2001, p. 151)

Palmaria palmata (L.) Kuntze, also called dulse, dillisk, dilsk or creathnach, is a red alga (Rhodophyta) previously referred to as Rhodymenia palmata (Linnaeus) Greville. It grows on the northern coasts of the Atlantic and Pacific oceans. It is a well-known snack food, and in Iceland, where it is known as söl, it has been an important source of fibre through the centuries.

History

The earliest record of this species is of St Columba's monks harvesting it 1,400 years ago.

Description

Dulse grows attached by its discoid holdfast to the stipes of Laminaria or to rocks. It has a short stipe, the fronds are variable and vary in 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 cm long and 30 - 8 cm in width which can bear flat wedge-shaped proliferations from the edge.

The reference to Rhodymenia palmata var.mollis in Abbott & Hollenberg (1976), is now considered to refer to a different species: Palmaria mollis (Setchel et Gardner) van der Meer et Bird.

Dulse is similar to another seaweed Dilsea carnosa (Schmidel) Kuntze, Dilsea, however, is more leathery with blades up to 30 cm long and 20 cm wide. Unlike Palmaria palmata it is not branched and does not have proliferations or branches from the edge of the frond. The older blades may split however.

Life history

The full life-history was not fully explained until 1980. Tetraspores occur in scattered sori on the mature blade, which is diploid. Spermatial sori occur scattered over most of the frond of the haploid male plant. The female gametophyte is very small stunted or encrusted, the carpogonia 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. After fertilization the diploid plant overgrows the female plant and develops into the tetrasporangial diploid phase attached to the female gametophyte. The adult foliose tetrasporophyte produces tetraspores meiotically.

Ecology

Palmaria palmata is to be found growing from mid-tide of the intertidal zone (the area between the high tide and low tide) to a depths of 20 m or more in both sheltered and exposed shores.

It is commonly found from June to September and can be collected by hand when the tide is out. When collected, small snails, shell pieces and other small particles can be washed or shaken off and the plant then spread to dry. Some collectors may turn it once and roll it into large bales to be packaged later. It is also used as fodder for animals in some countries.

Dulse is commonly used in Northern Ireland, Iceland and Atlantic Canada both as food and medicine. It can be found in many health food stores or fish markets and can be ordered directly from local distributors. In Ballycastle, Northern Ireland it is traditionally sold at the Ould Lammas Fair. A variety of dulse is cultivated in Nova Scotia and marketed as Sea Parsley, sold fresh in the produce section. Dulse is now shipped around the world. In Northern Ireland it is particularly popular along the Causeway Coast. Although a fast dying tradition, there are many who still gather their own dulse. Waste pipes have spoiled some sites.

Dulse can be found in some dietary supplements, where it is often referred to as "Nova Scotia Dulce", it is a good source of dietary requirements, a handful will provide more than 100% of the daily amount of Vitamin B6, 66% of Vitamin B12, a day's supply of iron and fluoride, and it is relatively low in sodium and high in potassium.

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. In Iceland the tradition is to eat it with butter. It can also be pan fried quickly into chips, baked in the oven covered with cheese, with salsa, or simply microwaved briefly. It can also be used in soups, chowders, sandwiches and salads, or added to bread/pizza dough. Finely diced, it can also be used as a flavour enhancer in meat dishes, such as chili, in place of monosodium glutamate.

Distribution

Palmaria palmata is the only species of Palmaria found on the coast of Atlantic Europe. It is to be found from Portugal to the Baltic coasts also on the coasts of Iceland and the Faroe Islands. It also grows on the shores of Arctic Russia, Arctic Canada, Alaska, Japan and Korea.

Infections, galls, malformations and diseases

Galls, possibly produced by nematodes, copepods and 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. Ann. Bot. 37 : 151 - 152.

• Pueschel, C.M. 1979. Ultrastructure of the tetrasporogenesis in Palmaria palmata (Rhodophyta). J. Phycol. 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. p. 1 - 136. Memorial University of Newfoundland Occasional Papers in Biology.

External links

• AlgaeBase
• Palmaria palmata on the Encyclopedia of Marine Life of Britain and Ireland
• Traditional And Modern Use Of Seaweed In Ireland Also shows Ascophyllum nodosum being collected.
• http://www.marlin.ac.uk/species/Palmariapalmata.htm Marlin - Palmaria palmata
• http://seaweed.ucg.ie/algae/rhodophyta.lasso