Common marine algae that are "feathery green"

NameNotes
variously branched mossy feather weed Bryopsis hypnoides (bryopsidaceae)
Key criteria: Large (to 15 cm) feathery species growing in deep lower shore pools and subtidally; epilithic. Typically occurring in sheltered habitats. Relatively easy to identify except for discrimination from its congener B. plumosa; common and widespread in the area as indicated. Mid to lower intertidal and pools. epilithic lower intertidal intertidal subtidal sheltered pool

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.