Phylum: Chlorophyta   Family: Ulotricaceae

Ulothrix subflaccida Wille, 1901

Some authorities regard this species as freshwater but (Brodie, et al. 2007) note: 'Widely distributed in fully marine and brackish waters where sheltered to moderately wave-exposed.'

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