- Kingdom: Animalia
- Phylum: Cnidaria
- Class: Anthozoa
- Subclass: Hexacorallia
- Order: Actiniaria
- Suborder: Nyantheae
- Family: Metridiidae
- Scientific name: Metridium senile
- Norwegian: sjønellik
The plumose anemone, also called frilled anemone, has a wide base, sometimes 12 cm across. The column may grow to a height of 50 cm. The color of the cylinder and the tentacles can be in shades of white, yellow, orange and brown. Large specimens may have a thousand tentacles.
It is usually found attached to rocks or other hard surfaces. The depth range is from the subtidal zone and down to 100 meters.
It is common around the British Isles and the north-west Europe, from France to Scandinavia. Reports from the Pacific Ocean, may be of a different species.
The seawater.no's standard reference on taxonomy, MarBEF, denotes the position of the Metridiidae family within Actiniaria as undetermined (incertae sedis on latin). Most other sources seem to agree that the family belongs to Nyantheae. There are some uncertainty whether different forms of the plumose anemone could be separate species. Once again, perhaps genetic studies eventually will provide the answers.