MACOI - Portuguese Seaweeds Website

Class:

Florideophyceae

Genus:

Palmaria Stackhouse

Species:

Palmaria palmata

Authority:

(L.) Kuntze

Description:

Reddish brown, membranous or leathery, flattened fronds, 50-300 (-1000) mm long, arising from a discoid base, usually with a small stipe expanding gradually to form simple or dichotomously and palmately divided fronds, often with characteristic marginal leaflets. Blade very variable in shape, having broadly ovate to narrowly linear segments.

Original publication: [Weber, F. & Mohr, D.M.H.] (1805). Einige Worte über unsre bisherigen, hauptsächlich carpologischen Zergliederungen von kryptogamischen Seegewächsen. Beiträge zur Naturkunde 1: 204-329.

Download PDF from Algaebase

Original description: Download PDF from Algaebase

Key characteristics: The palmate branching with its finger-like extensions is very characterstic; most plants have marginal proliferations at the base. Young plants can be less leathery and may be thin and slippery.

Similar species: The finely-divided forms are sometimes misidentified as Gracilaria multipartita, the latter is, however, much thicker, and recognisably fleshy.

Link for Algae Handbook (Pereira, 2010).

Name History

Adjective (Latin), lobed or divided in the manner of an outspread hand with the sinuses between the lobes pointing to the place of attachment (Stearn 1973).

Biogeography

Palmaria palmata grows along the northern coasts of the Atlantic and Pacific oceans, as far north as Arctic Canada and Russia, and as far south as Portugal in Europe, and New Jersey and California in the United States. In the western Pacific, the southern range of Palmaria palmata includes Japan and Korea.

Uses and compounds

This is a common red seaweed found between the tides on rocky shores and is named for its resemblance to the palm of the human hand (Latin, palma). In Ireland, Scotland and England, it is known as Dillisk or Dulse. In Irish, two names are used: Creathnach (feminine) and Duileasc (masculine). These names actually express different forms of what appears to be a single biological entity. Creathnach is a smaller, narrower form that generally grows on small mussels on wave-swept shores, and is sometimes known as "Shell-dulse" in English; this form is more popular in many places.Duilleasc, on the other hand, is used for a larger, broader form that grows directly on rocks or on kelp.

The use of dulse is known in Ireland since at least the twelfth century when it was mentioned in a poem describing the duties of monks:

Seal ag buain duilisg do charraig,
seal ag aclaidh,
seal ag tabhairt bhídh do bhoctaibh,
seal i gcaracair. A while gathering dillisk from the rock,
a while fishing,
a while giving food to the poor,
a while in a cell.

Regulations governing the collection of dulse were introduced in Iceland in the thirteenth century, and the Icelandic sagas (eleventh century onwards) describe one of the heroes being given dulse in milk to lull him into sleep prior to being killed.

Dulse is good to eat, but only after being dried. In a fresh state it is leathery and unpalatable. After sun-drying and proper storage, it is a very pleasant plant to chew. It has very little fat and only a small amount of proteins and cellulose, but is very rich in trace elements and vitamins, particularly vitamin A. Dulse contains large amount of several unusual carbohydrates including an unusual short-chained one, floridoside, and this can form up to 30% of the dry weight. This may account for its palatability.

Scotland, Norway, Iceland and eastern Canada all produce small amounts of dulse for human consumption. In Ireland about 20 dry tonnes are sold each year, mainly in the west and north-east. It is particularly popular in the working class areas on north Belfast where its use is likely to have come, along with the name 'dulse' from Scotland. At present natural dulse is in short supply.

All sorts of claims are made for dulse. According to a herbal published in Dublin in 1726 (Threlkeld's Synopsis stirpium hibernicarum…, as Fucus palmam humanam referens):

"But in Dublin men chew it like Tobacco when dry, carrying it in their Pockets for that end, which destroys worms, and gives a Relish to Beer, as Anchoves and Olives to Wine; it is commended against Women's longing."

The matter of it being a vermifuge may be due to the kainic acid content. Dulse used to be sold in the Galway Egg and Butter Market and was reputed to be an good remedy for a hangover; it is still occasionally sold in vegetable and fishmonger shops in Galway. Nowadays, dulse is often used in chowders and fish dishes, as a condiment, and even in desserts and bread.

Other uses: Palmaria palmata is a good source of dietary requirements; it is rich in potassium, iron, iodine and trace elements, and relatively low in sodium. A small amount can provide more than 100% of the daily amount of Vitamin B6, 66% of Vitamin B12, iron and fluoride. It has a slight nutty flavor, and has a long tradition in the cuisines of many Northern European cultures. Palmaria palmata is also a traditional food in maritime North America, used in condiments, soups, and appetizers. Younger parts of the fronds are considered the most tender and edible. It can be eaten raw. Palmaria palmata is also used as fodder for a variety of animals in many countries, as pet supplements, and sometimes as an agricultural fertilizer.

Over 100 types of products with Palmaria palmata have been identified so far by SIA, from Canada, United States, UK, Ireland, Italy, France, Spain, New Zealand, and Australia. There are various forms, such as powder, flakes, granules, and bulk leaves. Palmaria palmata is sold as a seasoning and spice, and also as a salt substitute. It can be smoked, served in a condiment, a chutney, a pesto, or as a Japanese-style gomasio. Palmaria palmata is sold in liquid, powder, and tablet form as a dietary and nutritional supplement, and is also in energy drinks. It is in eye gels, facial cleansers, moisturizers with sunscreen, bath salts and bath soaks, and massage oils. Palmaria palmata is in shampoos, conditioners, soaps, cleansing creams, hand creams, and shaving creams, and is certainly one of the more versatile and widely used types of commercial seaweeds.

Harvesting: Harvesting of Palmaria palmata mostly occurs in western Europe and in Atlantic Canada and Maine in the United States.

Harvesting Techniques: Palmaria palmata is often harvested from June through September, picked by hand at low water; care should be taken to leave the holdfast, in order to enable re-growth the following season. It is sometimes brought to drying fields or spreading grounds and put through a shaker to remove snails, shell pieces, and other foreign matter. The fronds of Palmaria palmata are sometimes spread thinly on netting and left to dry, and eventually rolled into large bales to be packaged or ground later.

References

Braune, W. (2008). Meeresalgen. Ein Farbbildführer zu den verbreiteten benthischen Grün- Braun- und Rotalgen der Weltmeere. pp. [1]-596, 266 pls. Ruggell: A.R.G. Gantner Verlag.

Irvine, L.M. & Guiry, M.D. (1983). Palmariales. In: Seaweeds of the British Isles. Volume 1. Rhodophyta, Part 2A Cryptonememiales (sensu stricto), Palmariales, Rhodymeniales. (Irvine, L. Eds) Vol.1 (2A), pp. 65-98. London: British Museum.

Loiseaux-de Goër, S. & Noailles, M.-C. (2008). Algues de Roscoff. pp. [1]-215, col. figs. Roscoff: Editions de la Station Biologique de Roscoff.

Habitat:

Marine species, on rock, mussels and epiphytic on several algae, intertidal (at all levels but particularly near low water) and shallow subtidal , especially on upper part of Laminaria hyperborea stip

Common names:

English: Dulse

Common names used in commerce, often for edible algae
grannogh; dillisk; main de mer {Fr}; handed fucus {Eng}; "fucus, handed"

Other names: an chreathnach, an duileasc, blom, crannach, creathnach, darusu, dillisk, dilsk, dilysg, duileasc, dulse, goémon à vache, Hauttang, Irish dulse, palmariale, palmera de mar roja, palmeria do mar vermelha, purple dulse, purple laver, raudsoll, red dulse, rood lapwier, rödsallat, sauesoll, sea kale, sea parsley, sheep weed, smalatare, sol, søl, söl, soll, söll, varette; previously known as Rhodymenia palmata

Type information:

Basionym: Fucus palmatus Linnaeus

Type locality: “Ad oras atlantica” (Linnaeus 1753: 1162). Lectotype: L 910.184.2889 (Irvine & Guiry 1983: 68). Notes: Linnaeus’'s description was taken from Van Royen (1740) and a lectotype has been selected from his herbarium (which Linnaeus examined).