Which types of seaweed are edible

A. The most common sort of seaweed is the finely branched red and green seaweed called carragheen, found on the coastline in the UK For centuries, Scottish, West Country and Irish cooks used carragheen as a setting agent for blancmanges and jellies.

It can also be bought from Caribbean stores, because it is traditionally used in the West Indies to make a spcied milk shake, which is reputed to have aphrodisiac qualities.

Other edible seaweeds include the giant kelps - long brown ribbons and hand-shaped fronds, which wash ashore at low tide. In the past, these were boiled and served with butter as a vegetable, made into soups, or dried and eaten as a tangy seasoning snipped over food.

Two other useful traditional seaweeds are dulse and sea lettuce. Dulce is most popular in Ireland, where it's mixed with potatoes and butter, for instance in a potato champ. An old-fashioned Scottish recipe combines dulse, milk, potato, butter, lemon juice and black peper to make a fragrant vegetarian seabroth. In Brittany, dulce is boiled with kelp to make pain d'algues; in Iceland, it's snipped as a garnish over haddock.

Sea lettuce, recognisable as tender sheets of green, is usually served chopped or fried to crispiness in France.

Q. What about laver bread

A. Laver is a thin, delicate seaweed that clings like shiny black plastic to exposed rocks around the coast. It has long been enjoyed by Hawaiians, Chinese and the Japanese, and by the Native American Tswatainuks, who eat it with creamed corn. It's also a traditional Welsh dish, served for breakfast with smoked bacon. In Wales, the laver is commercially harvested west of Swansea, boiled up on an industrial estate in the village of Penclawdd, and the black-green puree is sold as laverbread in markets in Cardiff, Swansea and Brecon. It's often rolled in oatmeal and crisply fried.

Laverbread tastes a little like olives with a marine undertone. Laver is also sharply sweetened with Seville orange juice to make a sauce for sewin (sea trout) and sweet Welsh mutton.

Q. Which country eats the most seaweed

A. Of the 20 different seaweeds commonly eaten in Japan, which is probably the largest consumer, five - nori, kombu, wakame, hijiki and arame - are generally available in the UK in dried form. Nori is Japanese laver, sold as tissue-thin squares, perfect for wrapping meat or vegetables, and for sushi. It's also an essential ingredient of Japanese green tea broth.

Kombu - Japanese kelp, is usually sold in tough, dried strips which soften when soaked, and it's used in many sauces and soups.

Wakame is one of Japan's most popular seaweeds in soups, eaten raw or lightly cooked and sprinkled with salt.

Q. Which seaweed is the stuff served in Chinese restaurants

A. It's not, the dark green tangle, usually deep fried and served with sugar and salt, is actually finely shredded greens.

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By Katharine MacColl