RX Seaweeds checklist

A provisional and simplified Checklist of the commoner and larger seaweeds recorded or likely to occur in the wider coastal area of East Sussex to Kent – from the Atlas of British Seaweeds.

Most microscopic as well as larger species are included and are listed below alphabetically under the three Families. Rhodophyceae, Phaeophyceae and Chlorophyceae. Some have common names which are given.

Much more recording needs to be done to have an up-to-date account of the species and status of Seaweeds along the Hastings coast.

Andrew Grace



Seaweed species are highly adapted to particular niches and there are many species. Seaweeds are algae, primitive plants some of which are associated with the microscopic phytoplankton of the sea while others are larger and attached to physical surfaces in or near the sea by means of holdfasts. These basal structures act as physical anchors for the plant but they do not take in water or nutrients and therefor are not roots as such. However as plants they have chlorophyll and produce energy by photosynthesis in the same manner as do plants on the land. Carbon dioxide and water are synthesised into glucose – and oxygen is released as a part of the process.

Seaweeds are highly adapted to a stressful environment influenced by the gravitational effect of the Moon on the sea. There is a community ecology with zonation of seaweed types depending on the environmental conditions on any part of the coast. This in turn provides many types of habitat for other marine life.

Seaweeds reproduce themselves in a complex life history, with a tiny stage and a larger spore-producing stage.

Rhodophyceae (Red Seaweeds) have green chlorophyll mixed with phycoerythrin, a red pigmentation.

Phaeophycea (Brown Seaweeds) contain the pigment fucoxanthin.

Chlorophyceae (Green Seaweeds) have green chlorophyll.




Aglaothamnion hookeri

Ahnfeltia plicata

Calithamnion tetragonum

Calliblepharis ciliata Widespread.

Callophyllis laciniata

Catenella caespitosa

Ceramium gaditanum

Ceramium virgatum Distinctive. Grows on other seaweeds.

Chondria dasyphylla

Chondrus crispus Irish Moss. Rocks and pools of the lower shore. Widespread.

Corallina officinalis Coral Weed. Pink chalky red.

Cryptopleura ramosa

Delesseria sanguinea Sea Beech. Shape of a red Beech tree leaf attached to rock.

Dilsea carnosa Red Rags. Distinctive bright red.

Dumontia contorta Long, twisted fronds. Widespread.

Erythrodermis traillii

Furcellaria lumbricalis Many branced tufts of reddish-brown fronds.

Gelidium pusillum

Griffithsia corallinoides

Gymnogongrus crenulatus

Halurus equisetifolius Sea Mare’s-tail.

Halurus flosculosus Tufted fronds of stiff hairs.

Heterosiphonia plumosa

Hildenbrandia rubra

Hypoglossum hypoglossoides

Lomentaria articulata Bead-weed.

Mastocarpus stellatus Grape Pip Weed.

Melobesia membranacea

Membranoptera alata

Nitophyllum punctatum

Osmundea hybrida

Osmundea pinnatifida Pepper Dulse. Fern-like with strongly built fronds.

Palmaria palmata Dulse. Distinctive broad fronds and small holdfast.

Phyllophora crispa

Phyllophora pseudoceranoides

Phymatolithon laevigatum Maerl. Unattached coralline.

Phymatolithon lenormandii Maerl. Unattached coralline.

Plocamium cartilagineum

Plumaria plumosa Feathery branches.

Polyides rotundus

Polysiphonia elongata

Polysiphonia fucoides

Polysiphonia lanosa An epiphyte, growing on Egg Wrack.

Polysiphonia nigra

Polysiphonia stricta

Porphyra leucosticta Laver.

Porphyra linearis Laver.

Porphyra purpurea Laver.

Porphyra umbilicalis Laver.

Pterothamnion plumula Whorles of divided branches on fronds.

Rhodochorton purpureum

Rhodomela confervoides

Rhodothaminiella floridula

Rhodymenia holmesii

Rhodymenia pseudopalmata

Schottera nicaeënsis

Stylonema alsidii



Ascophyllum nodosum Egg Wrack. Grows on other seaweeds. Widespread.

Cladostephus spongiosus Slender fronds and branchlets. Widespread.

Desmarestia viridis

Dictyota dichotoma Yellowish flattened ribbon fronds with forked tips. Widespread.

Ectocarpus fasciculatus

Ectocarpus siliculosus

Elachista fucicola

Fucus serratus Serrated Wrack. Widespread with distinctive serrate fronds.

Fucus spiralis Spiral Wrack. Widespread. An upper shore seaweed.

Fucus vesiculosus Bladder Wrack. Sheltered rocky shores. Widespread.

Halidrys siliquosa Sea Oak. Distinctive fronds. Widespread.

Hincksia granulosa

Laminaria digitata Kelp. Conspicuous shiny brown frons. Widespread.

Laminaria hyperborea Cuvie.A large seaweed commonest in the southwest.

Laminaria saccharina

Leathesia difformis Punctured Ball Weed. Spherical yellow-brown on rocks and other seaweeds.

Myrionema strangulans

Pelvetia canaliculata Channel Wrack. Mainly in Western Britain.

Petalonia fascia Distinctively twisted fronds. Grows on rocks.

Petroderma maculiforme

Pseudolithoderma extensum

Pylaiella littoralis

Ralfsia verrucosa

Sargassum muticum Wireweed. Slender branched with round bladders. Introduced.

Scytosiphon lomentaria Beanweed. Tubular fronds with constrictions are distinctive.

Sphacelaria cirrosa

Sphacelaria nana

Spongomena tomentosum

Stragularia clavata

Stypocaulon scoparium Sea Flaxweed. Tufted brown on lower shores.



Acrochaete viridis

Acrosiphona arcta

Blidingaria marginata

Blidingaria minima

Bryopsis hypnoides

Bryopsis plumosa Hen Pen. Feathery tufted green seaweed quite widespread.

Chaetomorpha linum Delicate tangled tufts in rockpools. Widespread.

Chaetomorpha melagonium

Cladophora albida

Cladophora rupestris Cladophora. Rock pools as a mat of delicate tufted strands.

Cladophora sericea

Enteromorpha compressa

Enteromorpha intestinalis Gutweed. Widespread on rock pools.

Enteromorpha linza

Enteromorpha prolifera

Monostroma grevillei

Prasiola stipitata

Pringsheimiella scutata

Pseudendoclonium submarinum

Rhizoclonium riparium Dense springy carpets of threads.

Rhizoclonium tortuosum

Spongomorpha aeruginosa

Ulothrix flacca

Ulothrix implexa

Ulva lactuca Sea Lettuce. Attached to rocks in sheltered areas and can be found on the beach.

Ulva rigida

Urospora penicilliformis

Urospora wormskioldii


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