Colony of Botryllus schlosseri on rock. Image width ca. Grows on a variety of stable substrata including algae and artificial substrata. Thrives in sheltered areas including docks. Flat or fleshy colonies with zooids 2-4 mm across arranged in conspicuous star shaped systems, each with a central cloacal opening.
Colonies vary greatly in colour including green, violet, brown and yellow.
Botryllus schlosseri , Star ascidian.