Phylum: Chlorophyta   Family: Ulvaceae

Ulva linza Linnaeus, 1753

Double Ribbon Weed

Common in rock-pools in the mid to upper shore zones. Bright green, almot luminous in spring with good light, growing up to 30 cms.

References: 
Brodie, Maggs & John (2007) - Green Seaweeds of Britain and Ireland