Zoobotryon verticillatum is a common bryozoan in the Indian River Lagoon (IRL), and may have the largest biomass of all IRL bryozoa. Its colonies are arborescent, with trifurcately branching stolons of approximately 0.5 mm in diameter. Zooids are sac-like and arranged along 2 sides in rows. Zooids measure approximately 0.4 - 0.6 mm in height. The lophophore has a diameter of approximately 0.320 mm, and bears 8 tentacles. A large gizzard is present. Young colonies have transparent stolons. Calcium carbonate is absent in exoskeletons of this species.