Phylum: Rhodophyta   Family: Callithamniaceae

Aglaothamnion gallicum  (Nägeli) Halos ex Ardré, 1970

A rarely recorded species that can grow to 50 mm tall. Epiphytic on a number of seaweed species from the lower intertidal zone

References: 
Maggs & Hommersand (1993) - Seaweeds of the British Isles, Volume 1 Rhodophyta, Part 3A Ceramiales