| Name | Notes |
|---|---|
| Bonnemaison's hook weed | Bonnemaisonia hamifera (bonnemaisoniaceae ) |
| Key criteria: | Gametophytes medium-sized with distinctive crozier-shaped modified branches. Mainly spring and early summer with a south-western distribution. Sporophytes forming small tight pom-poms in intertidal pools mainly on Corallina officinalis and are more widely distributed than the gametophytes; both phases reproducing independently by vegetative means. An introduced species. intertidal pool |
| diamond cartilage weed | Chondria dasyphylla (rhodomelaceae) |
| Key criteria: | Large (to 20 cm) species with branched cylindrical axes. Grows mostly in the shallow subtidal on mobile substrata such as pebbles and shells where it is sometimes abundant. It is comparatively easy to identify. It is widespread in the area although the lack of records here from eastern Scotland north-east England reflects its rarity there. shallow subtidal subtidal |
| spiny straggle weed | Gelidium spinosum (gelidiaceae) |
| Key criteria: | Distinctive small to medium-sized species. Generally found on lower intertidal rocks or in the shallow subtidal. Sometimes associated with sponges. Western distribution with a few sites in north- eastern England. lower intertidal intertidal shallow subtidal subtidal rock |
| hairy basket weed | Spyridia filamentosa (ceramiaceae) |
| Key criteria: | Large robust filamentous species more or less confined to the subtidal of moderately sheltered coasts where it often grows detached. It is unmistakable microscopically although its general appearance can be nondescript. As shown here it is confined to the south-west of Britain and in Ireland with its northern limit at Loch Ryan. subtidal sheltered |
| harpoon weed | Asparagopsis armata (bonnemaisoniaceae ) |
| Key criteria: | Gametophytes medium-sized with distinctive barbed branches. Mainly summer and autumn and found in the lower intertidal to shallow subtidal often entangled with Ulva. Sporophytes forming small loose pom-poms generally in intertidal pools or in the shallow subtidal. Gametophytes common only in south-western locations; sporophytes more widespread; both phases reproducing independently by vegetative means. An introduced species. lower intertidal intertidal shallow subtidal subtidal pool |
| Brogniart's thread weed | Brongniartella byssoides (rhodomelaceae) |
| Key criteria: | Large (to 20 cm) polysiphonous species bearing spiraled monosiphonous filaments. It grows primarily subtidally in a wide range of habitats both on bedrock and on mobile substrata; also growing epiphytically. It is comparatively easy to identify microscopically but otherwise can be confused with Dasya. It is widespread in the area although it appears to be relatively uncommon in eastern England and occurs northwards to Norway. epiphyte subtidal rock |
| slender cartilage weed | Chondria capillaris (rhodomelaceae) |
| Key criteria: | Large (to 25 cm) species with branched cylindrical axes which grows mostly in the shallow subtidal on mobile substrata such as pebbles and shells. It is comparatively easy to identify. As shown here it has a south and south-western distribution in Britain and occurs up to the NE coast of Ireland with scattered records from islands off western Scotland. generally on sheltered often silty shores. shallow subtidal subtidal sheltered |
| iridescent cartilage weed | Chondria coerulescens (rhodomelaceae) |
| Key criteria: | Fairly small (to 8 cm) species with branched cylindrical axes that show a distinctive bright blue iridescence. Rare growing in the shallow subtidal on pebbles in mud in sheltered inlets. As shown here it is confined to south and south-western coasts of Britain and is unknown in Ireland. shallow subtidal subtidal mud sheltered |
| Mrs Griffiths' little flower | Halurus flosculosus (ceramiaceae) |
| Key criteria: | Large (to 15 cm) branched filamentous species growing both intertidally and subtidally in a wide range of habitats including rock pools. This species is common and relatively easy to identify as indicated by the large number of records shown here. intertidal subtidal rock pool |
| fine elongate siphon weed | Polysiphonia elongella (rhodomelaceae) |
| Key criteria: | Fairly large (to 20cm) much-branched polysiphonous species that grows subtidally on sheltered coasts. It is widespread but uncommon on western coasts; northern and eastern records require re-evaluation. subtidal sheltered |
| whorled bush weed | Sphondylothamnion multifidum (ceramiaceae) |
| Key criteria: | Large robust filamentous species more or less confined to the subtidal where it is commonest on wave-exposed coasts. It is common and relatively easy to identify. The records shown here indicate that it is found more frequently along south-west coasts although it also occurs in western Scotland its northern limit. subtidal exposed |
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.