A chameleon rose was a flower that changed color with the mood of its owner.
In 2364, Wyatt Miller gave Deanna Troi a chameleon rose as a gift. The rose initially had golden leaves and a golden stem. The petals were blue when Miller held it and turned red, then white when Troi held it. They later turned purple while still in Troi's hands. (TNG: "Haven")
According to the Star Trek Encyclopedia (4th ed., vol. 1, p. 131), the chameleon rose was native to Betazed.