Fan Weed

Overview

Flabellia petiolata, commonly known as Fan Weed or Udotée, is a perennial green alga found in the Mediterranean Sea and the temperate eastern Atlantic Ocean. This distinctive species is easily recognized by its fan-shaped, non-calcified thallus, which is attached to the substrate by a small stalk.

Appearance

The alga typically reaches up to 10 cm in height and features a green, fan-like frond marked by lighter, concentric lines. As the plant ages, the edges of the fan may become torn, and the surface is frequently colonized by various epiphytes.

Distribution & habitat

This species is commonly found on hard substrates, including rocky surfaces and steep walls. It is often associated with shaded environments, though it can also be found in more illuminated waters during warmer summer months. It is frequently observed in the lower reaches of seagrass meadows and can thrive at depths ranging from just below the surface down to 120 meters.

Biology & behavior

As an autotrophic organism, Flabellia petiolata produces its own energy through photosynthesis. During its reproductive phase, the thallus may take on a whitish appearance due to the development of reproductive cells. It is known to host a diverse community of associated marine fungi. The sea slug Bosellia mimetica is recognized as a primary predator of this alga, often blending in with its green, fan-shaped structure.