Bryopsidales, Dichotomosiphonaceae
Avrainvillea obscura (C. Agardh) J. Agardh

In natural habitat.
Photo Data
- Place
- : Samui Island, Surat Thani.
- Depth
- : 1.0 m
This species has flat, wedged or fan-shaped blades. The blade margin is fibrous to slightly erose. The holdfast is small and less than 2 cm in length. The branching of the blade filaments are dichotomous with constrictions at branching points. The apices of the filament are round. This seaweed is found on rocks covered with sand in lower intertidal to subtidal zones along calm shorelines and in tidal pools.

Fresh specimen.

Microscopic view of the blade filament with rounded apex and constrictions (arrows) at branching point.