P. homomalla contains the bioactive lipid prostaglandin A2 15-acetate methyl ester at about 3% of total wet weight.

The calyces from which the polyps protrude are typically not projecting, but may be slightly raised above the surface of the coral.

[2][3][4] P. homomalla is found growing on reefs in the Caribbean Sea, the Gulf of Mexico, the Bahamas, and Florida.

[5] Killifish, family Cyprinodontidae, and yellowhead wrasse (Halichoeres garnoti) vomit after being fed gelatine pellets containing prostaglandin.

The prostaglandin produced by the coral seems to offer a chemical defence and act as a deterrent to predatory fishes.