Description:
Ivory tree coral is a slow-growing, delicate and branching coral that forms thicket-like colonies as much as 5 feet tall and 6 feet wide.  Tree-like branches, formed during coral calcification, extend from the base.  Two different growth forms have been identified.  Shallow water Oculina occurs at depths to 120 feet.  This form is typically golden-brown in color due to the presence of symbiotic algae called zooxanthellae.  Shallow water specimens grow 4 - 10 inches, with an average size of 6 inches. The other growth form, deepwater Oculina, grows at depths between 130 - 500 feet.  Because of its depth, deepwater Oculina lacks symbiotic zooxanthellae, and appears white in color. Deepwater corals sometimes form massive coral heads and reefs, and can measure 10 - 60 inches; with a typical size of 40 inches. 

Habitat:
In subtropical shallow waters of 7 - 120 feet, Oculina varicosa occurs as a semi-isolated, low-growing colony, patchily distributed on coquinoid reef.  However, in deeper waters of 230 - 325 feet it can occur as a massive, coalescing aggregate having substantial topographical relief.  Depth ranges from 10 - 500 feet. Oculina varicosa can withstand moderate wave exposure on near-shore reefs.

Similar Species:
Ivory tree coral is similar in appearance to a related species, Ivory bush coral, Oculina diffusa, which also occurs in the Indian River Lagoon.  It is differentiated from O. diffusa by size, depth and growth habit.  Bush coral grows to depths of 40 - 75 feet, tends to be smaller than tree coral, and has shorter branches.

Range:
Oculina varicosa occurs from North Carolina to Bermuda and the West Indies.  It occurs sparsely in the Indian River Lagoon and on ledges in intracoastal waterways, but can be abundant on shallow near-shore reefs and on shelf edge banks off east central Florida.