Characters: Colonies are phaceloid; corallites are closely compacted, 20-40 millimetres diameter. Small solitary polyps are common. Primary septa are very exsert and are conspicuous underwater. First and second order septa plunge steeply near the centre of the corallite. There are no columellae. Polyps have large tubular tentacles with knob-like tips. Colour: Usually pale grey or green, with distinctively coloured tips to the tentacles. Similar species: Euphyllia glabrescens. Small Plerogyra sinuosa have similar, although larger, skeletal structures. Living colonies of Plerogyra have grape-like vesicles, rather than tentacles, extended during the day. Habitat: Shallow reef environments. Abundance: Uncommon but conspicuous.