Asperococcus bullosus J.V.Lamouroux
Description: Thallus tan to dark brown, membranous, hollow and irregularly inflated to bullate, to 100 cm long and 2-12 cm in diameter, with a small holdfast, and a short, slender stipe expanding suddenly to an inflated thallus with irregular constrictions.
Reproduction: Sori of sporangia rounded to elongate, scattered, 100–350 µm across, containing sessile, pyriform to clavate, unilocular sporangia.
Habitat: Lower intertidal and shallow subtidal; mainly epiphytic. Western and southern coasts of Britain and Ireland.