Description: Thallus is golden brown, wiry, bushy, reaching 3 m (9 ft) tall, with a main axis and alternate branching and attached by a small discoidal holdfast. The small blades have toothed margins, and small rounded floats usually occur singly and lack a pointed tip. Habitat: An invasive perennial accidentally introduced from Japan, it occurs mainly in the low intertidal and shallow subtidal of protected to semi-exposed habitats. Similar taxa: Cystoseira geminata