''Polysiphoides fucoides'' (Hudson) Greville (''Vertebrata fucoides'')Bunker, F.StP.D., Brodie, Juliet, A., Maggs, C.A. and Bunker, A.R. 2017. ''Seaweeds of Britain and Ireland.'' Second Edition. Wild Nature Press, Plymouth, UK. is a common marine algaHardy, F.G. and Guiry, M.D. 2003 ''A Check-list and Atlas of the Seaweeds of Britain and Ireland.'' The British Phycological Society. in the Division
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 ...
.
Description
''Polysiphonia fucoides'' is a relatively small seaweed. It grows as branched, cylindrical tufts reaching 30 cm or more in length. The branches are themselves densely branched, the main branch usually distinct. It is attached by matted branches which produce rhizoids. The branches are composed of a central axes of cells surrounded by 11 to 21 pericentral cells all of the same length.
Cortication
A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.holdfast, with the cells growing down in grooves between the pericentral cells.Maggs, C.A. and Hommersand, M.H. 1993. ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales'' The Natural History Museum, London The branching may resemble ''Vertebrata thuyoides'', but the branches of ''B.thuyoides'' are corticated almost to the tips.
Reproduction
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 reproductio ...
. Spermatangial branchlets occur near the apices of the branches. Cystocarps are borne on short stalks. and tetrasporangia occur in series towards the apices of the branches.