| Name | Notes |
|---|---|
| tassel weed | Carpomitra costata (sporochnaceae) |
| Key criteria: | A distinctive subtidal species with a western pattern of distribution. subtidal |
| Cutler's many cleft weed | Cutleria multifida (cutleriaceae) |
| Key criteria: | A quite distinctive subtidal plant on stones and bedrock with a predominantly southern and western distribution pattern. This species is represented by an erect blade-like dichotomously branched summer annual sexual phase and a prostrate membranous perennial asexual phase the latter being more widely distributed. subtidal rock |
| netted wing weed | Dictyopteris polypodioides (dictyotaceae) |
| Key criteria: | A distinctive southern and western distributed species locally abundant in the subtidal contributing to the underflora of kelp forests. subtidal |
| divided net weed | Dictyota dichotoma (dictyotaceae) |
| Key criteria: | A widespread and abundant species forming regularly dichotomously branched flattened blades often characterized by a conspicuous iridescent colouring. A summer annual found in intertidal pools and throughout the subtidal. intertidal subtidal pool |
| no common name | Dictyota spiralis (dictyotaceae) |
| Key criteria: | A southern species rarely recorded probably due to its resemblance to Dictyota dichotoma. ~ |
| peacock's tail | Padina pavonica (dictyotaceae) |
| Key criteria: | A distinctive fan-shaped southern species reported for lower intertidal pools and the subtidal. Irish records refer either to ephemeral populations or misidentifications. lower intertidal intertidal subtidal pool |
| wooly seed weed | Sporochnus pedunculatus (sporochnaceae) |
| Key criteria: | A distinctive species confined to southern and western coasts. It occurs in the subtidal on small stones gravel etc especially in silty areas during the spring and summer. subtidal |
| dotted peacock weed | Taonia atomaria (dictyotaceae) |
| Key criteria: | A fairly distinctive species locally abundant in the south and south-west becoming progressively rarer further north. It is characteristic of places with intermittent sand scour. sand |
| penny weed | Zanardinia typus (cutleriaceae) |
| Key criteria: | A subtidal plant with a horizontally expanded flattened thallus covering silty boulders and bedrock underneath Laminaria hyperborea forests. A southern species reaching its northern distribution limits on southern and western shores. subtidal rock |
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.