During its first year of growth, the bryozoan encrusts the substratum forming a flat base before it starts to grow into an erect colony.
Flustra forms annual growth lines, similar to rings in a tree, which show when it has lain dormant over the winter months, usually October to February (Eggleston, 1963).
Colonies off the Welsh coast have been known to grow to at least 12 years of age (Stebbing, 1971).
The microscopic structure of Flustra foliacea was first described in September 1665 by Robert Hooke (1635–1703). In the book, Micrographia, Hooke illustrated a variety of objects, some biological and some manmade, which he had viewed through various lenses. He was the first person to apply the word cell to biological objects.