Cetraria

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Cetraria aculeata
[“Spiny heath lichen”; syn. Coelocaulon aculeatum, Cornicularia aculeata]

USES: Dye (Scotland, Canary Islands)

In Scotland and the Canary Islands a red-brown dye for woolens was made out of this lichen (Uphof 1959).

Cetraria aculeata contains protolichesterinic acid (Brodo et al. 2001).

Cetraria ericetorum
[“Iceland lichen”; partial syn. Cetraria crispa]

FOLK NAMES: Aouq (Aouk’) (Yuqpik: Alaska); Jaegel [Name also applied to other lichens reindeer eat, Cladina spp., Cetraria islandica, Cetraria ericetorum, Cetrariella delisei, and Stereocaulon spp.] (Saami: northern Scandinavia)

USES: Food (Yuqpik: Alaska), Animal forage (Saami: northern Scandinavia)

The Yuqpik of southwest Alaska used Cetraria ericetorum subsp. ericetorum [syn. Cetraria crispa] as food. It was chopped up and added to various soups as a flavoring. (Wilson 1979; and Oswalt 1957).

Cetraria ericetorum is recognized by the Saami of Northern Scandinavia as one of the preferred foods of free-range reindeer, and they call these lichens Jaegel. SEE: Cladina spp. for more information on lichens as forages.

Cetraria ericetorum contains lichenesterinic acid, as well as two other unidentified substances (Brodo et al. 2001).

Cetraria islandica
[“Iceland Lichen”, “Iceland Moss”]

FOLK NAMES: Brødmose or Broedmåså [lit. bread moss], Matmåså [lit. food moss], or Svinmåså [lit. swine moss] (throughout Iceland, Norway, Sweden, and Finland)

USES: Food (Europe, especially Scandinavia), Medicine (Europe)

Cetraria islandica has a rich history of being used medicinally in Europe. In 1737 Linnaeus considered Cetraria islandica to be a very important medicine. He said it was used as an emollient and tonic in chronic affections (Perez-Llano 1944). In 1838 Lindley reported that in Europe Cetraria islandica was a favorite of some practitioners for treating pulmonary and digestive organs, particularly in phthisis, chronic catarrh, dyspepsia, and chronic dysentery. It was also frequently given to sick persons as alimentary substance after the bitterness was removed by washing it in a weak alkali solution. In 1846 the Pharmacopoeia Universalis listed several medicinal uses for the lichen (Saklani and Upreti 1992). Until Lagasca reported finding Cetraria islandica in Puerto de Pajares in 1883, the people of the Iberian Peninsula (Spain) were importing it for medicine from northerly regions (González-Tejero et al. 1995).

Uphof (1959) reported that Cetraria islandica was still being used commercially in Scandinavia, Germany, Switzerland, and Austria. It was employed as a substitute for salve bases in the preparation of emulsions, as a laxative, as a culture medium for bacteria, and to reduce the bitter taste in some drugs (Uphof 1959; Piorkowski 1916, cited in Perez-Llano 1944). Saklani and Upreti (1992) report that Cetraria islandica is widely sold in health food stores in Sweden to treat lung disease, diabetes, and catarrh. Airaksinen et al. (1986) that the lichen is also used in Sweden as an expectorant, appetizer and roborant, and to soften the gut contents. Cetraria islandica is used in traditional medicine in Spain to treat catarrh, asthma, and to reduce inflammation (Muntané 1991, cited in González-Tejero et al. 1995). Wheelwright (1935) also confirms the use of Cetraria islandica used by herbalists to teat catarrh, and says that it is used as a mild mucilaginous tonic. Perez-Llano (1944) records that meals made with Cetraria islandica were said to be good for dyspeptics, and Brodo et al. records that the species was also used as a laxative. Although it is apparent that Cetraria islandica was used for a wide range of ailments, it was generally used for problems related to the respitory or digestive systems.

Both Llano (1944b) and Uphof (1959) record that Cetraria islandica has been used in the tanning industry. The astringent depsides in the lichen are what makes it useful for tanning (Llano 1944b). Cetraria islandica has also been used in Iceland to dye wool a brown colour (Uphof 1959).

Cetraria islandica, along with several other lichens, is recognized by the Saami of Northern Scandinavia as a preferred food of free-range reindeer and they call these lichens Jaegel. Icelanders, as well as Scandinavian farmers and Saami in northern Scandinavia, would harvest Cetraria islandica and use it as feed for domestic animals (Llano 1944b). Smith (1921) records that in 1921 Cetraria islandica was being stored in large quantities and used as fodder for horses, oxen, cows, and pigs by Icelanders. Cetraria islandica was often called Svinmåså [lit. swine moss] in Iceland because of its use as animal feed (Airaksinen et al. 1986). Cetraria islandica was thought to be quite good as animal feed by Icelanders, but normally Cladina spp. would be used for animal feed instead and the Cetraria islandica would be saved for human use (Airaksinen et al. 1986). Before the lichen was fed to animals it was usually processed to remove bitterness. SEE: Cladina spp. for more information on lichens as food for domestic livestock or forage for free-range animals.

Cetraria islandica, along with several other lichens, has been used to produce molasses in northern Russia. SEE: Cladina spp. for more information on this use of lichens. Cetraria islandica has also been used to make brandy in northern Europe and northern Russia. This process was most commonly used with Cladina rangiferina, but several other lichen species have been used. SEE: Making Brandy from Lichen under Cladina rangiferina.

Cetraria islandica was the most important lichen for human food in Europe. It was called Brødmose [lit. bread moss] or Matmåså [lit. food moss] in Scandinavia and was as a regular food, as a famine food, and as a tasty desert. Cladina rangiferina was used in the same way on occasion, but Cetraria islandica was much preferred. Cetraria islandica was most commonly eaten in Iceland and Norway, and to a lesser extent in the rest of Scandinavia. In times of famine it was eaten throughout northern Europe, especially in Norway, Great Britain, and the Soviet Union (Airaksinen et al. 1986). The last major collection of Cetraria islandica in Finland and Sweden happened during WWI at the recommendation of the authorities (Airaksinen et al. 1986). It was occasionally sold commercially in Iceland and Scandinavia as Iceland Moss. Icelanders made the most use of it, and would collect great masses of it yearly (Llano 1944b). In Iceland the Jónsbók (law book) in 1280 mentions Gros (lichen, probably Cetraria spp. and Cladonia spp.) as a natural product that could not be collected without landowner permission (Airaksinen et al. 1986).

Before Cetraria islandica could be eaten it had to be processed to remove the bitter lichen acids and debris. The lichen was picked over by hand and the lower part of the lichen along with any extraneous pine needles or other foreign material was removed (Airaksinen et al. 2001). Llano (1944b) records that the lichen was then boiled in lye. Airaksinen et al. (1986) records that the lichen was soaked in an alkali solution for 1 to 5 days, and then often boiled afterwards in water. Originally a solution of wood ash was used, thick enough to float a potato (about 2%). Later on a 0.5% to 1.0% solution of sodium or potassium carbonate was used instead (Airaksinen et al. 1986). Afterwards the lichen was thoroughly rinsed, oven dried, and finely ground into flour (Llano 1944b; Airaksinen et al. 1986). According to Airaksinen et al. (1986) this treatment decreased the weight of the lichen, so that one kilogram of raw lichen would produce half a kilogram of processed flour. In this processed state the lichen could be stored for many years (Llano 1944b).

The flour of Cetraria islandica was used to make bread, gruel, porridge, salads, and jelly. To make bread the lichen flour was mixed with other meal. Airaksinen et al. (1986) record that it was usually mixed with rye or oat meal, and Perez-Llano (1944) records that it was sometimes mixed with mashed potatoes as well as cereals. Llano (1944b) records that bread was often made in northern Finland using Cetraria islandica and rye flour. According to Llano (1944b) the bread was made with 75% lichen flour and 25% other meal, but Airaksinen et al. (1986) discovered that processed Cetraria islandica flour was toxic to mice if fed in their ration in a concentration greater than 25%. Airaksinen et al. (1986) state that the lichen flour traditionally was not used as more than 25% of the bread. The mixture of lichen flour and grain meal was baked like bread. It was traditionally recommended that the bread had to be baked for at least 10 minutes or it would make you sick (Airaksinen et al. 1986). The finished bread had a strong flavor like wheat bran, but with a hot taste, and kept well (Llano 1944b).

Cetraria islandica flour was mixed with ship’s flour because it made the bread less friable and less subject to weevil attack (Perez-Llano 1944). It was also used to make other dishes that are described by Llano (1944b). It was mixed with elm cortex and grain and boiled in lots of water to make broth. To make a porridge a container was filled a third with lichen and then boiled with water until it was thick. The top broth and scum was skimmed off and then it was salted to taste, cooled until hard, and eaten with or without milk. It could be redried in an oven and used as bread. To make gruel, one pound of finely cut lichen was added to 1.5 - 2 quarts of water and cooked until half the water had evaporated. It was then strained and the filtrate could be flavored with raisins or cinnamon. The residue was eaten as a salad with oil, egg yolk, and sugar. When the broth was allowed to cool it hardened into a jelly (formed by the lichenin and isolichenin). Milk was added and it was used as a desert and mixed with lemon juice, sugar, chocolate, or almonds. Lindley (1838) says that this jelly is very tasty if flavored with white wine. Nelson (1951) records that the jelly can be mixed with milk to form a highly nutritious demulcent drink. According to Airaksinen et al. (1986) the jelly is especially good if served with acidic berries like cranberries that help to mask the slightly acrid taste.

Interestingly, Lindley (1838) records that Sir John Franklin and his party could barely eat Cetraria islandica even when they were starving because of its bitterness. This is undoubtedly because they were not processing it right.

Brodo et al. (2001) reports that Cetraria islandica usually contains fumarprotocetraric, protolichenesterinic, and lichenesterinic acid. According to Airaksinen et al. (1986), European populations of the lichen that they tested contain mainly fumarprotocetraric and alloprotocesteric acids, and a very small amount of usnic acid.

Some of the medicinal properties of Cetraria islandica have been supported in clinical trials. Kempe et al. (1997) performed randomized trials on patients who had undergone surgery on their nasal septum and thus were subjected to prolonged mouth breathing following surgery. Cetraria islandica, administered daily in the form of 0.48 mg ‘Iceland moss’ lozenges, was found to prevent both dryness and inflammation of the oral cavity.

Perez-Llano (1944) reports that cetraric acid extracted from Cetraria islandica was found to have no ill effects on animals when fed to them or injected into their blood. It did induce peristaltic movement in the intestine. Cetraric acid has also been used as a nerve excitant (Perez-Llano 1944).

There is also some research to indicate that protolicheresterinic acid from Cetraria islandica may be valuable in the treatment of ulcers and cancers, and in AIDS prevention. It has been documented that protolicheresterinic acid has in vitro activity against Helicobacter pylori (Ingolfsdottir et al. 1997) and DNA polymerase activity of human immunodeficiency virus-1 reverse transcriptase (Pengsuparp et al. 1995). Protolicheresterinic acid was also found to be antiproliferative and cytotoxic to T-47D and ZR-75-1 cell lines cultured from breast carcinomas, and to K-562 from erythro-leukemia (Ogmundsdottir et al. 1998). Protolichesterinic acid may perform these functions by inhibiting 5-lipoxygenase, and this would also contribute to protolichesterinic acid's reported anti-inflammatory actions (Ogmundsdottir et al., 1998).

Poulsson (1906; cited in Perez-Llano 1944) made bread from both Cetraria islandica and Cetraria nivalis and tested them on humans. Between 46 and 49% of the carbohydrates in Cetraria islandica were digested, but Cetraria nivalis caused such intestinal disturbances that the experiment had to be stopped.

Airaksinen et al. (1986) also did experiments on the edibility of Cetraria islandica. They found that Cetraria islandica was toxic to mice when fed to them in a ration of 50% lichen by mass. The mice all showed gastrointestinal symptoms and died. The lichen was a little less toxic if it was boiled for 10 minutes, and a bit better than that if soaked in wood ash solution for two days. Both of these procedures were often done when the lichen was traditionally prepared for human consumption. If both of these treatments were done the lichen was not near as toxic to the mice but it still killed them if they were fed the lichen in high concentrations for extended periods.

Traditionally, people would have eaten about 50% lichen by volume, which is about 25% by mass. Airaksinen et al. then fed rats a ration of 25% lichen by mass, after it was soaked in ash water for two days, boiled for ten minutes, and dried. Rats tolerated this ration quite well, but may have shown some signs of heavy metal poisoning from lead that was accumulated in the lichen.

Airaksinen et al. (1986) reports on the nutrient value of Cetraria islandica. The lichen was found to be 50-80% carbohydrate, 3% protein, 2.6% fat, and 0.75% ascorbic acid. The carbohydrate was lichenin and isolichenin, and after hydrolysis it yielded 97% glucose, galactose, and mannose. There was not much ash (1-2%) compared to higher plants, and not much calcium, but there were high ash concentrations of some elements such as aluminum, iron, nickel, cobalt, chromium, fluorine, and arsenic. Cetraria islandica was also found to absorb some toxic elements from the environment. It was particularly high in lead, but also high in cadmium and mercury. The natural radionuclides Po-210 and Pb-210, as well as Cs-137 and Sr-90 from nuclear test explosions, were also found to accumulate in the lichen.

Chatfield and Adams (1940; cited in Arnason et al. 1981) also did a nutrient analysis of Cetraria islandica and found it to be 13.7% water, 1.5% ash, 0% protein, 0% carbohydrate, and 2.4% fat. They obviously had some error in their methodology.

Cetraria juniperina
[syn. Lichen juniperinus]

NOTE: This name is cited in ethnographic literature but it is no longer a valid taxon. The species Cetraria juniperina is generally synonymous with the genus Vulpicida. In North America this name was applied to Vulpicida canadensis or Vulpicida viridis.