Vegetative and reproductive features of the Mediterranean red alga Chondrophycus tenerrimus (Cremades) comb. nov. (Rhodomelaceae, Ceramiales) are described. The species is characterised by the following features: 1) a basal system composed of a spreading basal crust from which many terete axes arise; 2) the production of two pericentral cells from each vegetative axial segment; 3) the presence of a palisade-like superficial cortical layer; 4) the absence of projecting superficial cortical cells; 5) the absence of longitudinally oriented secondary pit connections between contiguous superficial cortical cells; 6) the absence of lenticular thickenings in the walls of medullary cells; 7) the absence of intercellular spaces between contiguous medullary cells; 8) a perpendicular arrangement of tetrasporangia, each of which is produced from the second pericentral cell in each fertile segment; and 9) flask-shaped cystocarps with a slightly to prominent ostiole. Chondrophycus tenerrimus belongs to the subgenus Palisadi section Palisadi. Features that distinguish C. tenerrimus from C. papillosus (C.Agardh) Garbary et J.Harper, with which it has often been misidentified in the Mediterranean Sea, are given.
Ceramiales, Chondrophycus tenerrimus, marine algae, Mediterranean Sea, Rhodomelaceae, Rhodophyta