Marine Animal Encyclopedia
Mermaid’s Wineglass Acetabularia acetabulum
This curious little green alga grows in clusters on rocks or shells covered with sand in sheltered parts of rocky coasts within its range. Although it grows to 1 in (3 cm), it consists of just one cell. Its calcified frond appears white because it is encrusted with calcium carbonate, and it terminates in a small cup. The cup is made up of fused rays that produce reproductive cysts. The cysts are released after the remainder of the plant has decayed, and they then require a period of dormancy in the dark before they begin to germinate.