This anemone is white, brick red-orange, or brown. It can be up to 1 m tall when extended and has more than 100 long, slender tentacles, except in small individuals The edges of the oral disk are prominently lobed. The column has acontia, which may be shot out when disturbed; but does not have tubercles. Height to 50 cm and crown diameter to 25 cm. Taller than wide when fully extended, but can change its proportions dramatically. This species has only recently been distinguished from Metridium senile. Gotshall states that this species is exclusively white but I have seen orange and brown individuals much larger than 10 cm tall, and other authors also report colored forms. Brown individuals seem more common in California than in the Pacific Northwest.