In Greek mythology, Leuce (or Leuke) was the beautiful nymph, daughter of Oceanus. Hades fell in love with her and abducted her to the underworld. Leuce lived out the span of her life in Hades realm (kingdom). After Leuce death, Hades created a memorial of their love in the Elysian field, by transforming her into white poplar.
two sides of poplar leave
The white poplar was sacred to Hades. When Hercules return from the underworld, he was crowned with poplar leaves.