Seaweed
"Seaweed" is a colloquial term and lacks a formal definition. A seaweed may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. As these three groups do not have a common multicellular ancestor, the seaweed are in a polyphyletic group. In addition, some tuft-forming bluegreen algae (Cyanobacteria) are sometimes considered to be seaweed.
Stylonema alsidii
It is one of the algae of the Houtman Abrolhos, found off the coast of Western Australia. It is one of the red seaweeds of South Africa, including the seaweeds of the Cape Peninsula and False Bay.