The septa protrude slightly and are rounded and even; they are very neatly arranged, and cross the valley walls.

It can be distinguished from the otherwise similar Platygyra daedalea by the thickness of the corallite walls and the more rounded septa.

[1] Spawning of P. lamellina, a simultaneous hermaphrodite, occurs at night during the summer on a date determined by the phase of the moon; in the Red Sea, this is the three- to five-day period around the new moon in July and the similar period in August.

[4] Clusters of eggs and sperm are released by the corals, and these are buoyant and rise to the surface.

The slow development of the larvae is believed to be due to the absence of zooxanthellae, and these symbionts are acquired at the primary polyp stage in this species.