Thallus is up to 25cm high when fully grown and fertile, attached to a small holdfast. Leathery and wavy, dichotomous branching fronds have a prominent midrib. Apices of the fronds form large aerocysts, where the receptacles are also formed.
It is most fertile and erect during spring and early summer, but withers towards autumn. During low tide, it can lose up to 60% of its water, severely dehydrating in the process.
Upper and lower mediolitoral; forms a distinct “fucus” belt.
Historically widespread and common, endemic to the Adriatic sea; from Venice to Albanian coast. Nowadays, the species is very localised and rare, occasionally forming patches up to 2m2.
Acording to Verlaque et al (2019), the species should be considered vulnerable (VU) to extinction. Extinct in Slovenia since 2016 (Battelli, 2016). A strictly protected species in Croatia.