Mesogloia vermiculata (Smith) S.F.Gray
Description: Thallus cylindrical, muddy olive-brown, to 300 mm long. Frond soft and gelatinous, smooth main axis obvious, 2-5 mm wide, irregularly swollen and constricted; branching irregular, branches numerous, giving rise to secondary and tertiary branchlets. Pseudoparenchymatous, uniaxial, easily squashed to reveal a medulla of colourless assimilatory filaments 7-10 cells long, terminal cells, globose, up to 15-20 µm in diameter.
Habitat: Littoral; epilithic (sand covered rock and stone).
Key characteristics: Slimy, brown.