| Aspect: | Flat blades, usually green or green with blue or brown tones, that fork off in Y patterns - hence their English designation. Can spread over relatively wide surfaces. |
| Population: | Widespread. |
| Notable feature: |
Belongs to the Brown Algae category in spite of its usually predominent green colour (algae are subdivided into four colours: Brown, Green, Red and Blue-Green. |
| Environment: | Can grow over many substrates, and as exemplified by some of the photographs herewith, can even develop over leaf corals. |
| Behaviour: | - |