-Animals (Kingdom Animalia)

-Cnidarians (Phylum Cnidaria)

-Hydrozoans (Class Hydrozoa)

-Hydroids (Subclass Hydroidolina)

-Athecate Hydroids (Order Anthoathecata)

-Suborder Capitata

-Family Pennariidae

-Genus Pennaria

-Christmas Tree Hydroid (Pennaria disticha)

The Christmas Tree Hydroid (Pennaria disticha) is a marine cnidarian belonging to the class Hydrozoa. Named for its branching, tree-like appearance. Composed of polyps arranged along the branches; each polyp has a central mouth surrounded by tentacles. Found attached to hard substrates such as rocks, shells, and coral.