Ceramium sp. are red small algaes that don’t grow more than 30 cm tall. The axis of Ceramium sp. Consist in cells surrounded by smaller cells that form the cortex. 

In this genus it’s common that the continuous cortex encloses the axis, and in others the cortical cells form nodes at the junction of cells of the axes. 

This genus of red algae usually show irregular branching and are attached by unicellular or branched rhizoids.