Size
Colony height: reaching 15cm (6")
Recognition Characters
Grows in large, bushy tufts branching in all directions. Hydrocaulus can be branched or unbranched and is divided into internodes at regular intervals. Hydrothecal pedicels of varied length, with varied annulation either throughout pedicel or at both ends. Hydrothecae wine-glass shaped, transparent with a smooth rim. Polyps have approximately 20 tentacles in a single whorl.
Color
Brown with transparent to white polyps.
Habitat & Depth
Attach to other hydroids, seaweeds or octocorals. Shallow intertidal to 20m.
Distribution at GRNMS
Occasional. Can be found attached to Leptogorgia or rocks on the tops of ledges.
Geographic Range
Southeast coast of United States, parts of Caribbean, Gulf of Mexico
Behavior & Notes
Tiny medusae are formed with the cone-shaped gonothecae. Medusae are released during summer. Obelia is preyed upon by the sea slug Misea evelinaea tiny 0.1" (3mm) nudibranch with a translucent whitish-brown body, smooth rhinophores, and few laterally situated cerata with black specks.
Synonyms
Rupper and Fox 1988