Growth of Flustra foliacea (Bryozoa)

The perennial bryozoan Flustra foliacea L. has annual growth-checks which leave lines across the fronds. These growth-checks have been used to determine the age and the pattern of growth of the colonies in terms of height and numbers of zooids. Monthly samples have been used to find the annual growth cycle. Heavy encrustations of epizoites on the F. foliacea colonies reduce growth rate. As the fronds increase in height, frontal budding of zooids thickens, and thereby strengthens, the holdfast.