Cystoseira hoppei C.Agardh 1820, Cystoseira barbata (Stackhouse) C.Agardh 1820, Treptacantha barbata (Stackhouse) Orellana & Sansón 2019
Tall, dark-brown, single-axis algae that resembles a small tree, up to 1m tall. The cauloids can either be simple or complex, with smooth, but warty texture. Branches are cylindrical and well developed, but all are lost during the estivation period from summer to autumn. Fertile from winter to early summer.
Intertidal and subtidal sheltered areas; prefers shallow subtidal, but also forming enlcaves in deeper tide pools. Somewhat rare in deeper areas (down to 40m). Can be abundant in lagoons or sheltered bays.
Widespread and common, but showing signs of massive regression due to multiple environmental and anthropogenic factors.
- G. barbata f. barbata – a typical, single axis form, attached to a circular holdfast
- G. barbata f. repens – an unnatached form, often loosing the defined main axis. Occurs in shallow lagoons.