Plocamium cartilagineum
{{Short description|Species of alga}}
{{Speciesbox
|image =Plocamium cartilagineum Helgoland.jpg
|image_alt = Plocamium cartilagineum herbarium sheet
|image_caption = Plocamium cartilagineum herbarium sheet
|genus = Plocamium
|species = cartilagineum
|authority = (Linnaeus) P.S.Dixon
}}
Plocamium cartilagineum is a medium-sized red marine alga.
Description
File:Plocamium cartilagineum Miller.jpg
Plocamium cartilagineum is an erect red alga growing to 10 cm in length. The main axes is flattened with regular flattened branches on both sides. The branches are long and short alternately, the short ones on one side are opposite the longer on the other side. These longer branches bear two or three short curved branches in series, comb-like. The plants are fully corticated. This branching pattern is similar to Plocamium lyngyanum and Plocamium maggsiae the other European species which have only recently been distinguished.Bunker, F.StP.D., Brodie, J.A., Maggs, C.A. and Bunker, A.R. 2017 Seaweeds of Britain and Ireland. Second Edition. Wild Nature Press, Plymouth, UK {{ISBN|978-0-9955673-3-7}}Dickinson, C.I. 1963. British Seaweeds. The Kew Series
Habitat
Common on rock in the lower littoral and deeper to 30.Hardy, F.G. and Guiry, M.D. 2003 A Check-list and Atlas of Seaweeds of Britain and Ireland. The British Phycological Society {{ISBN| 0-9527115-16}}
Reproduction
File:Plocamium cartilagineum cystocarps.jpgs) visible.]]The plants are dioecious. The male structures are microscopic. The female cystocarps grow to 1 mm in diameter and are on the margins of the frond. The spermatangia are within the youngest branches in sori. The tetrasporangia are microscopic.
Distribution
Common all around the British Isles including Shetland and Channel Islands.Faeroes and Norway to Senegal, Mediterranean and Canary Isles.Dixon, P.S. and Irvine, L.M. 1977. Seaweeds of the British Isles Volume 1 Rhodophyta Part 1 Introduction, Nemaliales, Gigartinales British Museum (Natural History) {{ISBN|0 565 00781 5}}