| Name | Notes |
|---|---|
| common coral weed | Corallina officinalis (corallinaceae) |
| Key criteria: | Medium-sized articulated coralline. Segments medium to large generally longer than broad without a general fishbone arrangement of branches. Common on wave-washed rocks in pools often with an extensive base. Widely distributed. Epilithic and in rock pools. epilithic rock pool |
| no common name | Jania rubens var. rubens (corallinaceae) |
| Key criteria: | Medium-sized articulated coralline alga forming hemispherical tufts. Segments small cylindrical or slightly flattened. Mainly epiphytic on Cystoseira Halopithys and Cladostephus. Widely distributed with western orientation. epiphyte |
| coral maerl | Lithothamnion corallioides (corallinaceae) |
| Key criteria: | Occurring rarely as attached protuberant thalli on shells commonly as unattached profusely branching pinkish red rhodoliths with blunt-tipped branches. Quite common in southern England and western Ireland recorded in Scotland but all checked records there are Lithothamnion glaciale lower intertidal to subtidal. lower intertidal intertidal subtidal |
| pink plates | Mesophyllum lichenoides (corallinaceae) |
| Key criteria: | Occurring as a robust leafy epiphyte mainly on Corallina officinalis more rarely epilithic. Widespread in the south and west mid-intertidal to 8 m. epiphyte epilithic intertidal |
| Celtic maerl | Phymatolithon calcareum (corallinaceae) |
| Key criteria: | Occurring widely as an unattached richly branched mauvish-brown rhodolith drying to mauvish. Common on southern and western coasts subtidal or more rarely in intertidal pools. (Epilithic warty thalli occur southwards from France.) epilithic intertidal subtidal pool |
| no common name | Boreolithon van-heurckii (corallinaceae) |
| Key criteria: | Comprising minute uncalcified thalli growing on the surface of the hydroid Aglaosphenia attached to Halidrys. Probably intertidal. Known only from the original record at St Brelade on Jersey. intertidal |
| no common name | Choreonema thuretii (corallinaceae) |
| Key criteria: | Semi-endophytic species forming minute globular conceptacles protruding from segments of the geniculate corallines Haliptilon squamatum and Jania rubens. Probably intertidal to upper subtidal. Easily recognised but probably under-reported. endophyte intertidal subtidal |
| no common name | Corallina elongata (corallinaceae) |
| Key criteria: | Medium-sized articulated coralline. Segments small often broader than long usually with a general fishbone arrangement of branches. Common on wave-washed rocks. Generally western distribution. Under-recorded rock |
| erect clublet | Cordylecladia erecta (rhodymeniaceae) |
| Key criteria: | Medium-sized erect sparingly branched cylindrical fronds arising from an expanded basal crust. Epilithic in silty and sandy pools in lower intertidal pools and wave- washed ledges. Subtidal to 20 m. Widely distributed. predominantly western distribution. Occasional. epilithic lower intertidal intertidal subtidal sand pool |
| encrusting reds | Crouania attenuata (ceramiaceae) |
| Key criteria: | A small gelatinous species fairly rare growing epiphytically in lower shore pools and subtidally. It is difficult to confuse with other species. It is confined to the south- west of Britain and to southern Ireland. The record shown from Cardigan Bay may represent the northernmost for this species and the record from the Outer Hebrides is almost certainly erroneous. epiphyte subtidal pool |
| Burgundy maerl paint weed | Cruoria cruoriaeformis (cruoriaceae) |
| Key criteria: | Crustose plants found on shells and maerl fragments in the subtidal to depths of 5 m. Western distribution. Relatively common in appropriate habitats. subtidal depth |
| encrusting reds | Cruoria pellita (cruoriaceae) |
| Key criteria: | Crustose plants forming extensive growths on rock in the shallow subtidal. Common and widely distributed. shallow subtidal subtidal rock |
| no common name | Exilicrusta parva (corallinaceae) |
| Key criteria: | Thallus thin flat strongly adherent conceptacles flush and difficult to see. Epilithic on stones. Rare subtidal to c. 11 m. in depth. epilithic subtidal depth |
| no common name | Haliptilon squamatum (corallinaceae) |
| Key criteria: | Medium-sized articulated coralline alga. Segments medium characteristically shield-shaped branches curving elegantly. In pools on wave-swept shores and epiphytic on Cystoseira. South-western distribution as shown. epiphyte pool |
| no common name | Hydrolithon boreale (corallinaceae) |
| Key criteria: | Forming bright pinkish purple thin flat imbricating layers of thallus with prominent conceptacles mainly epiphytic on red and brown algae fairly common on stones and shells. Common throughout the area except eastern Scotland and England. Mostly intertidal but recorded to 8 m in depth. epiphyte intertidal depth |
| no common name | Hydrolithon cruciatum (corallinaceae) |
| Key criteria: | Forming thin thalli with prominent conceptacles mainly epiphytic on Zostera. Rare recorded from Dorset Wales Ayrshire and Ireland subtidal to 3 m. in depth. epiphyte subtidal depth |
| no common name | Hydrolithon farinosum (corallinaceae) |
| Key criteria: | Forming thin thalli with prominent conceptacles on Cystoseira foeniculacea. Rare seen only in Dorset but common in France and more or less cosmopolitan. Records require further investigation. epiphyte |
| no common name | Hydrolithon samoe_nse (corallinaceae) |
| Key criteria: | Forming thin flat thalli on stones conceptacles flush. Rare found only in the lower intertidal in Norfolk and Co Clare. lower intertidal intertidal |
| no common name | Hydrolithon sargassi (corallinaceae) |
| Key criteria: | Forming thin flat thalli with raised conceptacles that have a sunken dark centre. Uncommon known only from the south mainly epiphytic on Halopithys incurvus in the intertidal. epiphyte intertidal |
| slender beaded coral weed | Jania rubens var. corniculata (corallinaceae) |
| Key criteria: | As in Jania rubens var. rubens except that segments are slightly horned. Seemingly with a south-western distribution. epiphyte |
| no common name | Leptophytum bornetii (corallinaceae) |
| Key criteria: | Occurring as a smooth epilithic thallus with prominently raised rimmed tetrasporangial conceptacles. Occasional widespread but rare mid-intertidal to 1m. in depth. epilithic intertidal depth |
| no common name | Leptophytum elatum (corallinaceae) |
| Key criteria: | Occurring epilithically on rock or shell debris as a loosely attached somewhat undulating thallus with raised flat-topped tetrasporangial conceptacles. A recently described species recorded from Wales and southern England low intertidal or shallow subtidal. epilithic intertidal shallow subtidal subtidal rock |
| no common name | Leptophytum laeve (corallinaceae) |
| Key criteria: | Occurring epilithically on stones and rocks and epizoically on shells as a flat smooth pink thallus with large raised flat-topped tetrasporangial conceptacles. Infrequent known only from Scotland subtidal to 46 m in depth. epilithic epizoic subtidal rock depth |
| overgrowing paint weed | Lithophyllum crouaniorum (corallinaceae) |
| Key criteria: | Epilithic flat thallus reddish violet to grey with small flush conceptacles. Common and widespread intertidal to subtidal. epilithic intertidal subtidal |
| stone rose maerl | Lithophyllum dentatum (corallinaceae) |
| Key criteria: | Forming loose rhodoliths composed of dense interlocked lamellate branches. Subtidal rare in the area known only from Ireland. subtidal |
| no common name | Lithophyllum duckerae (corallinaceae) |
| Key criteria: | Forming loose rhodoliths with a knobbly surface. Subtidal. Rare known only as a specimen in the London Natural History Museum from Falmouth. subtidal |
| no common name | Lithophyllum fasciculatum (corallinaceae) |
| Key criteria: | Forming loose rhodoliths composed of terete branches. Rare subtidal. subtidal |
| no common name | Lithophyllum hibernicum (corallinaceae) |
| Key criteria: | Unattached branched thalli branches with cup-like apices. Rare known only as nineteenth-century specimens from Galway now in Foslieås herbarium in Trondheim Norway. ~ |
| common pale paint weed | Lithophyllum incrustans (corallinaceae) |
| Key criteria: | Epilithic thalli varying from flat to undulating to knobbly to labyrinthic mainly chalky pink to lavender tetrasporangial and bisporangial conceptacles appearing as sunken pin- points and characteristically dumb-bell shaped in VS (as can be seen in a roughly broken thallus). Abundant mid-intertidal to at least 8 m. epilithic intertidal |
| no common name | Lithophyllum nitorum (corallinaceae) |
| Key criteria: | Thalli epilithic more or less flat slightly glossy tetrasporangial conceptacles somewhat conical. Rare and apparently restricted to west and south-west coasts and the Channel Islands. Subtidal. epilithic subtidal |
| no common name | Lithophyllum orbiculatum (corallinaceae) |
| Key criteria: | Forming flat to very knobbly brownish pink thalli with flush tetrasporangial conceptacles that appear as flat pale dots. Abundant mainly growing on mid- to upper intertidal rocks in pools and gullies. upper intertidal intertidal rock pool |
| northern maerl | Lithothamnion glaciale (corallinaceae) |
| Key criteria: | Occurring as an attached protuberant crust or as a richly branched free-living reddish rhodolith. Common in the north rare in the south subtidal. subtidal |
| no common name | Lithothamnion lemoineae (corallinaceae) |
| Key criteria: | Occurring epilithically as a warty thallus with blunt somewhat tapering protuberances. Very rare recorded only in Northumberland mid-intertidal. epilithic intertidal |
| deep pink paint weed | Lithothamnion sonderi (corallinaceae) |
| Key criteria: | Occurring as smooth flat strongly adherent reddish thalli with prominent white conceptacles found on stones shells dead maerl and rocks. Common throughout the area subtidal. subtidal rock |
| no common name | Melobesia membranacea (corallinaceae) |
| Key criteria: | Occurring mainly as a thin membranous epiphyte on fleshy algae or occasionally epizoic or epilithic. Common throughout the area intertidal to subtidal. epiphyte epilithic epizoic intertidal subtidal |
| no common name | Phymatolithon brunneum (corallinaceae) |
| Key criteria: | Occurring as an epilithic flat brownish thallus with domed tetrasporangial conceptacles. A recently described species recorded from Dorset Devon Pembrokeshire the Channel Islands and Clare Island intertidal. epilithic intertidal |
| no common name | Phymatolithon laevigatum (corallinaceae) |
| Key criteria: | Occurring epilithically on rocks and stones as thinnish flat crusts with coarse watermarks in summer tetrasporangial conceptacles flush with thick rims. Widespread and common from mid-intertidal to 35 m. in depth. epilithic intertidal rock depth |
| no common name | Phymatolithon lamii (corallinaceae) |
| Key criteria: | Occurring epilithically on rocks and stones and epizoically on shells as a flat thallus with fine watermarks in summer; tetrasporangial conceptacles becoming deeply sunken. Widespread and fairly common from low intertidal to 90 m. in depth. epilithic epizoic intertidal rock depth |
| common shore paint weed | Phymatolithon lenormandii (corallinaceae) |
| Key criteria: | Occurring epilithically on rocks and pebbles and epizoically on shells and worm tubes as a thin mauve thallus with raised tetrasporangial conceptacles. Common the most abundant epilithic crustose coralline in the upper intertidal and recorded to 30 m. in depth one of the few crustose corallines able to tolerate lowered salinity in estuaries etc. epilithic epizoic upper intertidal intertidal rock depth brackish |
| common purple paint weed | Phymatolithon purpureum (corallinaceae) |
| Key criteria: | Occurring epilithically on rocks and stones (or sometimes unattached in maerl) as a rich reddish more or less flat thallus particularly on low intertidal rocks with flush tetrasporangial conceptacles surrounded by a thick rim often forming a distinct low intertidal band on rocky shores low intertidal to 45 m in depth. epilithic intertidal rock depth |
| no common name | Pneophyllum confervicola (corallinaceae) |
| Key criteria: | Forming very thin flat thalli with hemispherical conceptacles thalli sometimes unconsolidated and creeping. Quite common epiphytic on Cladophora fleshy red algae geniculate coralline algae and Zostera also on hydroids and bryozoans mainly intertidal but sometimes subtidal to c. 7 m. in depth. epiphyte intertidal subtidal depth |
| no common name | Pneophyllum coronatum (corallinaceae) |
| Key criteria: | Forming thin flat thalli with conical conceptacles that have multicellular filaments surrounding the pore. Epiphytic on a wide range of algae occasionally on Zostera rarely epilithic. Quite common mostly intertidal. epiphyte epilithic intertidal |
| no common name | Pneophyllum fragile (corallinaceae) |
| Key criteria: | Forming thin to somewhat thickened flat thalli with flush to slightly raised conceptacles. Thin thalli particularly abundant growing epiphytically on Zostera thicker thalli growing on red and brown algae. Common intertidal to c. 3 m. in depth. epiphyte intertidal depth |
| no common name | Pneophyllum limitatum (corallinaceae) |
| Key criteria: | Forming thin flat thalli with raised conceptacles in which the pore is surrounded by protruding filaments that make the pore look shiny. Quite common mainly intertidal epiphytic on Zostera and red algae. epiphyte intertidal |
| no common name | Pneophyllum lobescens (corallinaceae) |
| Key criteria: | Forming thin flat thalli with flush conceptacles pore surrounded by a calcified dome. Epilithic on rocks stones and glass epizoic on shells. Quite common low intertidal to c. 8 m. in depth. epilithic epizoic intertidal rock depth |
| no common name | Pneophyllum myriocarpum (corallinaceae) |
| Key criteria: | Forming thin flat thalli with conical conceptacles pore surrounded by a hyaline collar epilithic on rocks stones glass etc. epizoic on shells epiphytic on many fleshy red algae. Widespread but infrequent intertidal and subtidal. epiphyte epilithic epizoic intertidal subtidal rock |
| no common name | Titanoderma corallinae (corallinaceae) |
| Key criteria: | A small flat calcareous crust frequently found on Corallina officinalis occasionally on other geniculate corallines or epilithic. Common intertidal to subtidal. epilithic intertidal subtidal |
| no common name | Titanoderma laminariae (corallinaceae) |
| Key criteria: | Forming thin thalli almost exclusively as an epiphyte on Laminaria. Known mainly from southern England but probably under-recorded. epiphyte |
| little gem paint weed | Titanoderma pustulatum (corallinaceae) |
| Key criteria: | Forming thin flat mauvish pink thalli with convex conceptacles mainly epiphytic on fleshy algae more rarely epilithic. Only bisporangial conceptacles seen in the area very variable and described as a number of varieties in Seaweeds of the British Isles. Abundant mainly intertidal more rarely subtidal. epiphyte epilithic intertidal subtidal |
A Check-list and Atlas of the Seaweeds of Britain and Ireland. F. G. Hardy and M. D. Guiry. The British Phycological Society, 2003. ISBN 0 9527115 16 Seaweeds of Britain and Ireland. Bunker, Brodie, Maggs and Bunker. Seasearch 2012.