Vertebrata lanosa on Ascophyllum nodosum

''Polysiphonia lanosa'' (''Vertebrata lanosa'';Bunker, F.StP.D., Maggs, C.A., Brodie, J.A. and Bunker, A.R. 2017 ''Seaweeds of Britain and Ireland.'' Second Edition. Wild Nature Press, Plymouth Press, UK. ''Polysiphonia fastigiata'') is a common species of the red algae (

Rhodophyta Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

) often to be found growing on ''

Ascophyllum nodosum ''Ascophyllum nodosum'' is a large, common cold water seaweed or brown alga ( Phaeophyceae) in the family Fucaceae, being the only species in the genus ''Ascophyllum''. It is a seaweed that only grows in the northern Atlantic Ocean, also known ...

''.Maggs, C.A. and Hommersand, M.H. 1993, ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales''. The Natural History Museum, London

Description

The

thalli 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 ...

of this species form dense tufts, each tuft up to 7.5 cm generally attached by

rhizoid Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be u ...

s to the fronds of ''

Ascophyllum ''Ascophyllum nodosum'' is a large, common cold water seaweed or brown alga (Phaeophyceae) in the family Fucaceae, being the only species in the genus ''Ascophyllum''. It is a seaweed that only grows in the northern Atlantic Ocean, also known in ...

''. The erect cylindrical branches divide pseudodichotomously, that is forming two equal branches, one of the branches growing from a lateral branch. A transverse section shows an axial cell surrounded by 12 to 24 peraxial cells. The axial cell is large and occupies about one third of the diameter of each branch, best seen in transverse section. It is deep brownish red in colour. ''

Choreocolax polysiphoniae ''Choreocolax polysiphoniae'' is a minute marine parasitic alga in the division Rhodophyta. Description This small parasitic alga grows on the red alga ''Polysiphonia lanosa''. It grows as an irregular sphere on the fronds of the alga, reachi ...

'' is a small

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

alga which grows in a cushion-like manner to 1 mm in diameter on the branches of ''P. lanosa''. Choreocolax polysiphoniae (cross section)

Habitat

Widespread growing

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

ally on ''Ascophyllum nodosum'' wherever it is found and occasionally on other species of ''

Fucus ''Fucus'' is a genus of brown algae found in the intertidal zones of rocky seashores almost throughout the world. Description and life cycle The thallus is perennial with an irregular or disc-shaped holdfast or with haptera. The erect portion o ...

''.

Reproduction

The life history is a sequence of three phases:

gametangia A gametangium (plural: gametangia) is an organ or cell in which gametes are produced that is found in many multicellular protists, algae, fungi, and the gametophytes of plants. In contrast to gametogenesis in animals, a gametangium is a haploid ...

l, carposporangial and

tetrasporangia Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

l. Two of the phases are similar. The plants are

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

with spermatangial branches produced in tufts at the apices of the branches. The

cystocarp A cystocarp is the fruiting structure produced in the red algae after fertilization, especially such a structure having a special protective envelope (as in '' Polysiphonia)''. The structure from which carpospores are released.Maggs, C.A. and Hom ...

s are borne, usually singly. with a narrow ostiole from which

carpospore A carpospore is a diploid spore produced by red algae. After fertilization, the alga's carpogonium The carpogonium (plural ''carpogonia'') is the female organ in the Red Algae (Rhodophyta) which have a highly specialized type of reproduction. It c ...

s are released. The tetraspores occur in spiral series resulting from a simultaneous division into 4 equal spores.Irvine, L. M. 1983. p.101 ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 2A Cryptonemiales (sensu stricto) Palmeriales,'' Rhodymeniales. (British Museum)

Distribution

Common around the

British Isles The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles (O ...

and on the shores of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

from

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' ( Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

. Also

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is ...

and

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian province ...

References

{{Taxonbar, from=Q3556236 Rhodomelaceae