Cladostephus spongiosus (Hudson) C. Agardh
Also known as Cladostephus verticillatus.
Description: Frond narrow, tough and wiry, but soft to the touch, dark brown to black when dry, 2-3 mm wide and up to 250 mm long. Strongly resembling a bottle-brush plant or laboratory glass-cleaning brushes becasue of whorls of filaments arising from the main axis (below, magnified). Branching irregularly dichotomous. Plants with the whorls missing may resemble Ahnfeltia plicata. The coralline alga Jania rubens is frequently found growing as an epiphyte at the base of the fronds.
Habitat: On rocks and stones, gnerally in areas affected by sand, intertidal and shallow subtidal.
Distribution: Widely distributed and common.
Key characteristics: Bottle-brush appearance.