Mesophyllum expansum can reach a diameter of about 30 centimetres (12 in). Illuminated by artificial light they show a beautiful pink color, with hanging branches. These calcareous encrusting organisms can be observed occasionally near the surface and can reach a depth of 70 metres (230 ft).
This species is widespread in the Mediterranean Sea.
Mesophyllum expansum is a species of red alga belonging to the family Hapalidiaceae.
Cette espèce possède plusieurs synonymes taxonomiques :
Nomenclatura binomial Mesophyllum expansum