The mermaid's wineglass (Acetabularia crenulata) is one of the prettiest and most delicate plants that frequently elicits exclamations from first time viewers! Typically about 5 cm in height with the "wineglass" only 1 cm in diameter, it is found in shallow, sheltered waters attached to rocks and other shallow substrates. The "stem" and "wineglass" is partially calcified like many other green algae (Halimeda spp. or Cymopolia spp.).  Amazingly, each "stem" and "wineglass is actually a single huge cell.