Caulerpa flexilis is a species of fern-like green algae. Its branches are connected by runners, and feature shorter side branches up their length. These branches are covered in branchlets called ramuli, that are forked near the base. This particular variety has denser ramuli, is more robust than C. flexilis var. flexilis, and the side branches are in pairs sprouting from opposite sides of the main branch, giving it a flatter appearance.