''Flustra foliacea'' is a species of bryozoans found in the northern Atlantic Ocean. It is a

colonial animal In biology, a colony is composed of two or more conspecific individuals living in close association with, or connected to, one another. This association is usually for mutual benefit such as stronger defense or the ability to attack bigger prey ...

that is frequently mistaken for a

seaweed Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

. Colonies begin as encrusting mats, and only produce loose fronds after their first year of growth. They may reach long, and smell like lemons. Its microscopic structure was examined by

Robert Hooke Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that ...

and illustrated in his 1665 work '' Micrographia''.

Taxonomic history

''Flustra foliacea'' was studied as early as 1665, when

published observations of various organisms and materials made with an early microscope. It was first given a

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

in 1758, when Carl Linnaeus included it in the

10th edition 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. I ...

of his ' as ''Eschara foliacea''. In later publications, Linnaeus divided bryozoans into more than one genus, and so the species came to be called ''Flustra foliacea''. It is the type species of the genus ''

Flustra ''Flustra'' is a genus of bryozoans belonging to the family Flustridae. The genus has a cosmopolitan distribution. Species Many formerly included species have been moved to different taxa. The following species are currently recognised: *'' Fl ...

''.

Description

''Flustra foliacea'' is often mistaken for a

, but is actually a colony of animals. The fronds can reach a height of and have rounded ends. They have a strong aroma of lemons. It differs from the superficially similar ''

Securiflustra securifrons ''Securiflustra'' is a genus of bryozoans belonging to the family Flustridae. The species of this genus are found in Europe, North America, southernmost South America. Species: *'' Securiflustra bifoliata'' *'' Securiflustra securifrons'' ...

'' by the tendency of the frond branches to become markedly wider towards the tip. Each zooid is roughly rectangular, with 4–5 short spines at the distal end and 13–14 tentacles around the lophophore.

Distribution and ecology

''Flustra foliacea'' has a wide distribution in the north Atlantic Ocean, on both the European and American sides. It is restricted to colder sublittoral waters, and reaches its southern limit in northern Spain. The fronds of ''Flustra foliacea'' are often used by other animals as a substrate to live on. Such epibionts include other bryozoa such as ''

Crista eburnea A crista (; plural cristae) is a fold in the inner membrane of a mitochondrion. The name is from the Latin for ''crest'' or ''plume'', and it gives the inner membrane its characteristic wrinkled shape, providing a large amount of surface area fo ...

'', hydroids, sessile polychaete worms and the porcelain crab ''

Pisidia longicornis ''Pisidia longicornis'', the long-clawed porcelain crab, is a species of porcelain crab that lives in the north-eastern Atlantic Ocean. It varies from reddish to white, and grows to a carapace width of . It was first named by Carl Linnaeus in 17 ...

''. Other animals feed on ''F. foliacea'', including the

sea urchin Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...

s ''

Echinus esculentus ''Echinus esculentus'', the European edible sea urchin or common sea urchin, is a species of marine invertebrate in the Echinidae family. It is found in coastal areas of western Europe down to a depth of . It is considered "Near threatened" in t ...

'' and ''

Psammechinus miliaris ''Psammechinus miliaris'' is a species of sea urchin in the family Parechinidae. It is sometimes known as the green sea urchin or shore sea urchin. It is found in shallow areas of the eastern Atlantic Ocean and the North Sea. Description ''P. ...

'' and the nudibranch '' Crimora papillata''; the pycnogonid ''

Achelia echinata ''Achelia'' is a genus of pycnogonids in the family Ammotheidae.Hodge, 1864 : List of the British Pycnogonida, with descriptions of several new species. Annals and Magazine of Natural History, ser. 3, vol. 13, p. 113–117. Species The follow ...

'' feeds preferentially on ''F. foliacea''.

Life cycle

''Flustra foliacea'' colonies only grow in spring and summer, which can result in visible annual growth rings. Breeding occurs between separate male and female zooids within the colony in autumn and winter. The cells produce outgrowths known as ''ovicells'', which contain

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

s and are visible from October to February. The larvae are released in spring and, after a short period, settle to the substrate. For the first year, colonies grow only along the surface (encrusting), with loose fronds only being formed in subsequent years. These are produced when two encrusting colonies meet, and the two edges that make contact begin to grow upwards, back to back. The total lifespan of a colony may reach 12 years. It is frequently found washed up on beaches after storms.

References

External links

* * * Also available a
Project Gutenberg
{{Taxonbar, from=Q2399981 Cheilostomatida Animals described in 1758 Taxa named by Carl Linnaeus