1) Coelenterate genus 2) Genus fungia 3) Mushroom corals 
• (n.) A genus of simple, stony corals; -- so called because they are usually flat and circular, with radiating plates, like the gills of a mushroom. Some of them are eighteen inches in diameter.
Fun'gi·a noun [ New Latin , from Latin fungus mushroom: confer French fongie .] (Zoology) A genus of simple, stony corals; -- so called because they are usually flat and circular, with radiating plates, like the gills of a mushroom. Some of them are eighteen inches in diamete...
[n] - mushroom corals
genus Fungia noun a genus comprising the usual mushroom corals