anemone is white, brick
red-orange, or brown. It can be up to 1 m tall when extended
has more than 100 long, slender tentacles,
except in small individuals The edges of the oral
disk are prominently lobed. The column
which may be shot out when disturbed (photo);
does not have tubercles.
Height to 50 cm and crown diameter to 25 cm. Taller than wide
fully extended, but can change its proportions dramatically.
species has only recently been distinguished from Metridium
(1994) states that this species is exclusively white but I
orange and brown individuals much larger than 10 cm tall, and other
also report colored forms. Brown individuals seem more common
California than in the Pacific Northwest.
Metridium giganteum Fautin, Bucklin,
and Hand, 1989
Common name(s): Giant plumose anemone
|Metridium giganteum on a dock at
Anacortes, with some M.
senile nearby. Height about 15 cm, crown diameter
about 13 cm.
|(Photo by: Dave Cowles Nov
How to Distinguish from
has a similar
form and coloration but grows only up to about 10 cm tall, has less
100 tentacles, and the oral disk is not prominently lobed.
Alaska to Santa
Catalina Island, CA. Especially common in Puget Sound, the
Islands, and the Strait of Georgia.
Subtidal to at least
200 m; occasionally found intertidally.
Attached to rocks, floating
docks, and pilings.
live many years. This species does not seem to reproduce
as does M. senile.
is said to be solitary, but I have frequently seen it in aggregations
Sares Head, though perhaps not as tightly packed together as one sees
senile on docks. The acontia
do not sting the skin but could definitely sting the eyes or
This species, which can be up to 1 m tall when extended, is said to be
the world's tallest polyp.
References: Note: References
older than 1989 do not distinguish
between M. senile
and Carlton, 1975
and Brusca, 1978
and Laurent, 1979
and Snook, 1955 (as Metridium dianthus)
and McConnaughey, 1985
et al., 1980
and O'Clair, 1998
et al., 1985
Fautin, D.G., A. Bucklin, and C. Hand, 1989. Systematics of
anemones belonging to the genus Metridium
with a description of M. giganteum, new
species. Wasmann J.
Biol. 47: 77-85
General Notes and
Observations: Locations, abundances,
These two individuals have been disturbed and have released threadlike
The individual on the left has released the acontia
from the mouth, while the one on the left has released an acontium
from a pore in the body wall.
Authors and Editors of Page:
Dave Cowles (2005): Created original page