Donate Take Action

Join us


Marine Animal Encyclopedia

Flaccid Green Seaweed Ulothrix flacca

Flaccid green seaweed is made up of many unbranched green filaments, which themselves consist of strings of cells. The filaments form soft, woolly masses or flat green layers that stick to intertidal rocks. Each filament of flaccid green seaweed is attached to its rock by a single cell called a basal cell, which may be given additional anchorage by outgrowths called rhizoids. Flaccid green seaweed reproduces by releasing up to a hundred gametes, each with two flagellae, from some of the cells. In another phase of its life cycle it is a single globular cell.

Flaccid Green Seaweed habitat mapzoom image
  • Class Ulvophyceae
  • Size Up to 4 in (10 cm)
  • Habitat Intertidal on various shore types
  • Water_temperature 32–68°F (0–20°C)
  • Distribution Northern Atlantic, Mediterranean, waters off South Africa, Pacific