Legendwood Trees
These trees of the Feywild thrive not only on the plane of Faerie, but also in the arcane rich world of The Shattered Oceans. In both worlds, they usually grow in small copses and have a propensity to develop into Treants (the chances of them turning to a Treant is greatly increased in the Feywild, but there is still a small chance of this happening on the Prime Material Plane). From time to time, Treants from the Feywild will jump a portal (or create one themselves!) into The Shattered Oceans and make an area of high magic (usually Chronomancy magic) their new home. These areas where they settle are usually very wild and sparsely populated. Like the previous residents, the Treants do not seek to be discovered by civilization, lest it tries to control and harness their powers, pushing it to destructive or otherwise uncharacteristic behavior.
Lunar elves consider the Legendwood Tree to be a sacred plant and only harvest the leaves for specific Rituals and Rites of Passage. It is very common to see one of these trees; large, old, and solitary, at the center of the villages of Lunar Elves. Although these elves primarily live in the Northern Tripartite, the Legendwood Tree is able to grow in nearly any climate: with the exception being the islands of Gholurai. It is cultivated by many mages and kept in the gardens/greenhouses of arcane universities and research centers throughout the world.
Under the light of the Full Moons, the leaves of the Legendwood tree shine between a spectrum of pearly and luminescent colors, with a single ancient Elven rune on each leaf. If the leaves are steeped into a tea and consumed during The Full Moons, they can reveal prophecies, forgotten lore and memories, or even spells unique to the Feywild. If it is consumed during the Dark Moons, these leaves will drive anyone foolish enough to consume them raving mad with the secrets of the Legendwood. Both Moon phases will cause extremely potent and vivid dreams in the imbiber. Those who seek out magic in their dreams can harvest the leaves on the Full Moons can dry them to be used in tea for three weeks after harvest: to tap into the Dream Magic for a longer period of time. If the leaves of the Legendwood are consumed during any other time, they have no effect and leave a potent, bitter aftertaste in the imbiber's mouth for 1d4+1 hours, after which the taste wears off.
Fascinating in its positives and negatives. I suspect it holds surprises for your players!