What are Hades' symbols for?

Answer 1

They are most often associated with a myth, such as a screech owl was what the gardener of Hades, Ascalaphus, was turned into that bird for telling that Persephone had eaten food from the Underworld by Demeter. A white poplar was sacred for being the metamorphosed form of Leuke, a lover of Hades. Minthe was of that same origion as a lover of Hades who was transformed by Demeter or Persephone into mint. Most symbols are then crude memory cues for the myth involving certain gods and goddesses.