White-plumed Anemone (Metridium farcimen)

Also known as the giant plumose anemone, the white-plumed anemone is a species of sea anemone found throughout the western seaboard of North America. Like most anemones, the giant plumose anemone is a carnivore and feeds on small invertebrates and zooplankton that swim into their stinging nematocysts.  White-plumed anemones have very long lifespans (with individuals living up to 100 years) and can grow fairly large and as such have few predators, although nudibranchs and large starfish have been observed feeding on them. 



Image Source(s)

Anthopleura elegantissima “Aggregating Anemone” Anthozoa

Olympic National Park, WA
June 1, 2013
Robert Niese

A very common intertidal resident here in the Puget Sound and on the open coast. If it’s big and green, it’s Anthopleura xanthogrammica. If it’s white and has very fine tentacles (usually subtidal, not intertidal) then it’s Metridium. Now you can identify 90% of the anemones you find in your backyard!