Desmarestiaceae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

brown algae Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and po ...

, one of two families in the order

Desmarestiales Desmarestiales is an order in the brown algae (Phaeophyceae). Members of this order have terete or ligulate (flat) pinnately branched thalli attached by discoid holdfasts. They have a sporphytic thallus usually aggregated to form a pseudo-par ...

.Guiry, M. D. & G. M. Guiry. 2013
Desmarestiales.
AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. The family gets its name from the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Desmarestia ''Desmarestia'' is a genus of brown algae found worldwide. It is also called acid weed, acidweed, ', sea sorrel, (), ', mermaid's hair, landlady's wig, or '. However, 'sea sorrel' can also specifically refer to '' Desmarestia viridis''. Mem ...

'', which is named after the French zoologist

Anselme Gaëtan Desmarest Anselme Gaëtan Desmarest (6 March 1784 – 4 June 1838) was a French Zoology, zoologist and author. He was the son of Nicolas Desmarest and father of Eugène Anselme Sébastien Léon Desmarest. Desmarest was a disciple of Georges Cuvier and Alex ...

(1784-1838). There are three

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

in this family. Two are

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

, '' Himantothallus'' (species name '' Himantothallus grandifolius'') and '' Phaeurus'' (species name '' Phaeurus antarcticus''). These are both

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...

.Peters, A. F., et al. (1997)
Phylogeny and historical ecology of the Desmarestiaceae (Phaeophyceae) support a Southern Hemisphere origin.
''J Phycol'' 33 294-309. The third genus, ''

'', has 30Guiry, M. D. & G. M. Guiry. 2013
''Desmarestia''.
AlgaeBase. National University of Ireland, Galway. Accessed 04 June 2013. to 40 species. Most species have narrow, localized ranges, but some ''Desmarestia'', such as '' D. ligulata'' and '' D. viridis'', have disjunct but global distributions. It is thought that the family began its evolution in the Southern Hemisphere and radiated north. It is now distributed across much of the world, but is largely absent from

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

regions. An exception being the possibly

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

'' D. tropica'' of the

Galápagos Islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

. These algae require colder water temperatures for the successful production of

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce t ...

s. Species of the Desmarestiaceae can grow large, with the

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

, the plantlike main part of the alga, reaching maximum lengths around 10 meters. They can be flattened or cylindrical, and narrow or many-branched. They are

oogamous Oogamy is an extreme form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immobile, while the small male gamete (also known as sperm) is mobile. Oogamy is a common form of an ...

, with microscopic

gametophyte A gametophyte () is one of the two alternation of generations, alternating multicellular organism, multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has on ...

s.Womersley, H. B. S
Family Desmarestiaceae (Thuret) Kjellman.
Electronic Flora of South Australia. Department of Environment, Water and Natural Resources. Government of South Australia. 2001. The thalli of some ''Desmarestia'' contain

vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic mo ...

s of

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

with a pH as low as 0.44. These likely evolved to deter predators. These algae have a very

sour The gustatory system or sense of taste is the sensory system that is partially responsible for the perception of taste (flavor). Taste is the perception produced or stimulated when a substance in the mouth reacts chemically with taste receptor ...

taste.Turner, N. J. and P. von Aderkas. ''The North American Guide to Common Poisonous Plants and Mushrooms''. Timber Press. 2009. pg. 116. They can also have a bad odor when they are removed from the water.Bremner, H. A. ''Safety and Quality Issues in Fish Processing''. CRC Press. 2002. pg. 235.

References

{{Taxonbar, from=Q3024485 Brown algae families Desmarestiales