IDENTIFICATION
Several species of Caulerpa used in aquariums have the potential to be invasive if released into the wild. Strains of Caulerpa taxifolia and Caulerpa racemosa have already blanketed thousands of acres of seafloor in the temperate waters of the Mediterranean.
Nearly all Caulerpa species have the common features of being bright green, having a long running stem called a stolon, and having a rubbery texture that holds its shape out of water. They generally have upright fronds of various shapes, and are secured onto the substrate by fine hairs called rhizoids.
Patches typically grow low to the bottom, often standing six to 12 inches high or more. Caulerpa can grow in calm or rough waters, on rock, mud or sand. Fragments do not float and Caulerpa has not been observed attached to floating docks or boat hulls.
It typically displays colonial growth patterns, with stolons extending out from the patch from multiple points. The spread of a patch of Caulerpa is very similar to the growth of iceplant, the common landscaping groundcover plant. Patch development arises from both extension of existing runners, as well as the establishment of new patches by broken-off vegetative fragments.
Below are images of species to watch for, shown in and out of the water, as small plants, and as large, dense patches. In addition pictures of other benthic plants and animals that have been misidentified as Caulerpa are included.