Ceramium bisporum (Ceramiaceae, Rhodophyta), a New Record for the Mediterranean Algal Flora

The diminutive marine red alga Ceramium bisporum Ballantine (Ceramiaceae, Rhodophyta) is reported for the first time in the Mediterranean Sea, where it grows as an epiphyte of Peyssonnelia rubra (Greville) J. Agardh. Vegetative and reproductive characteristics of the alga are illustrated and its occurrence along the Tuscan Archipelago coastline is discussed.