Moonlace

Moonlace is a plant given to Percy Jackson by Calypso in The Battle of the Labyrinth. Later while Percy is planting it, Nico di Angelo startles him by commenting "nice plant". This plant is bioluminesent, glowing silver and sprouts under moonlight. It seems to grow quite quickly when cared for as Percy remarks under his mother's care it was spreading quickly. Also, the book hints that it might have to be the full moon for the flower to be planted.