Simbelmynë
Simbelmynë was a small white flower that grew in particular abundance on graves and tombs, most famously on the Barrowfield of the Kings of Rohan beneath the walls of Edoras. Simbelmynë was the name of the flower in Rohan, meaning "Evermind", a reference to the memories of the dead on whose tombs the flower grew. The Elves called them Uilos.
Etymology
The spelling of this flower's name does not appear to be completely fixed. Within The Lord of the Rings, and in most other sources, its name is spelt simbelmynë. However, there is at least one recorded instance where Tolkien prefers symbelmynë. These variations do not affect the meaning of its name.
Inspiratoin
In appearance, Tolkien compares Simbelmynë to the European anemone, a small white flower growing among the grass.