Ceramium clarionense Setchell et Gardner is a typical member of the genus characterized by having barrel-shaped axial cells incompletely covered by cortical cells and by pseudodichotomous branching. The apices are slightly incurved, causing a forcipate appearance of the branch tips. The axial cells cut off seven to eight periaxial cells, each one laterally producing a pseudoperiaxial cell. The cortication is formed by the development of cells originating from both periaxial and pseudoperiaxial cells. The pattern of cortication of the nodes, considering the number of periaxial cells, presence of pseudoperiaxial cells and its derivatives, is the main taxonomic characteristic of this species and differentiates it from all related species.