Practical ecological knowledge for the temperate reader.

Turkish Towel - Chondracanthus exasperatus


Family Description:
"Most members of this family are flattened blades; they can have single, entire blades or be much-branched. The blades can be smooth or covered with short protuberances called papillae. Like other red algae, the characters that unite this family are details of the female reproductive apparatus and post-fertilization development. Tetrasporangia are cruciate and occur in internal sori." [NPC-E-flora]

"Although members of this family have an alternation of isomorphic generations, the two generations have different cell wall carbohydrates. When extracted, the carbohydrates of the gametophyte form a gel whereas those of the tetrasporophyte form a viscous liquid. These carbohydrates represent two different forms of carrageenan, an additive to most ice creams to keep them smooth, and to chocolate milk to keep the chocolate in suspension." [NPC-E-flora]

Species description:
"Turkish Towel usually forms a single, erect blade up to 50 cm (20 in) or more tall and about 20 cm (8 in) wide. It grows best in somewhat exposed locations, where the blade is rather thick and even somewhat stiff, but it also occurs in more protected waters where it tends to be thinner. In either case, the blade is rather irregular in outline although it tends to narrow at the top." [NPC-E-flora]

"The most distinctive feature of this species is that both sides of the blade are covered with a carpet of small outgrowths, giving the whole blade the rather fanciful appearance of a thick bath towel. Theseoutgrowths, which are called papillae, are associated with reproductive structures. The main blade can tatter and acquire holes with age, and can shrink and darken as well. When young, it is dark red to rich purple in color, and is iridescent when wet." [NPC-E-flora]

"Basally, the main blade tapers to a short stipe, which can also carry a few additional blades that are much smaller in size (less than 1 cm or less than 0.4 in tall). The holdfast at the lower end of the stipe is small and discoidal." [NPC-E-flora]

"This species can be a conspicuous member of the low intertidal-upper subtidal seaweed community in the southern area covered by this book, but it becomes much less conspicuous in the northern part of its range." [NPC-E-flora]

Habitat/Range: "Bathymetry: low intertidal and subtidal to 18 meters (60 feet). World Distribution: northern Southeast Alaska to Baja California, Mexico"

Other Local Chondracanthus Species

Information on other related species

Chondracanthus acicularis gathered from Portugal, in summer, contained 36.6-61.1% (Dry wt.) of carrageenan. In late summer it was found to contain 49.8% (dry wt.) Chondracanthus teedei var. lusitanicus harvested in late summer contained 41-57% carrageenan (dry wt.). That harvested in summer contained 58% (dry wt.)[MarineAlgae]


"Carrageenans are a family of linear sulphated polysaccharides that are extracted from red edible seaweeds. They are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. There are three main varieties of carrageenan, which differ in their degree of sulphation. Kappa-carrageenan has one sulphate group per disaccharide, Iota-carrageenan has two, and Lambda-carrageenan has three."[Wiki-1]

"In parts of Scotland and Ireland, where it is known by a variety of local and native names, Chondrus crispus is boiled in milk and strained, before sugar and other flavourings such as vanilla, cinnamon, brandy, or whisky are added. The end-product is a kind of jelly similar to pannacotta, tapioca, or blancmange." [Wiki-1]

Processing: "Carrageen gelatin can be prepared at home using the traditional recipe found in Diderot's Encyclopédie and used for centuries. 5oz rinsed Irish moss is cooked with 8 quarts of water for 10 minutes, stirred as it boils. Hard water should be mixed with 1/2 oz of borax. Two quarts of cold water are rapidly added to the hot brew, and after the mixture has cooled it is strained through a cloth. It is then cooled for 24 hours and becomes gelatinous." [Wiki-1]

"After harvest, the seaweed is dried, baled, and sent to the carrageenan manufacturer. There the seaweed is ground, sifted to remove impurities such as sand, and washed thoroughly. After treatment with hot alkali solution (e.g., 5–8% potassium hydroxide), the cellulose is removed from the carrageenan by centrifugation and filtration. The resulting carrageenan solution is then concentrated by evaporation. It is dried and ground to specification."[Wiki-1]


Page last modified on Sunday, November 28, 2021 10:29 AM