Colony of individual polyps (hydranths) joined by root-like network of tubular stolons at the base. Colony shape is feather-like (pinnate). Colour: dark brown, older stems often overgrown by pink coralline algae. Up to 8 cm long.
Stems of these hydroids often wash up on beaches. The hydroids grow and are fertile throughout the year. They are the only species in this genus group and are native to southern Australian and New Zealand waters. The species was probably originally collected from Western Australia by the French Baudin expedition in 1802. The type specimens are in the Natural History Museum, Paris, labelled as "Mers Australes ou de la Nouvelle Hollande".
On holdfasts of seaweed, especially stems of seagrasses.
Plankton or Particles
Generally not harmful but still able to sting bare skin.
- DSE Advisory List : Not listed
- EPBC Act 1999 : Not listed
- IUCN Red List : Not listed