It is said in order for the flower to show up, a Beast Tamer who has lost their Tamed Monster has to visit the white stone in the middle of the «The Hill of Memories». After which, the flower will start sprouting from the grass in the middle of the rock, the buds opening with a 'bell-like tinkling'.
Since Beast Tamers are few in numbers, the flower is quite expensive in SAO.
To revive a deceased Tamed Monster, the owner of the Tamed Monster has to drip the droplet of water in the middle of the flower onto the pet's «Heart». However, the item is only effective if it is used within three days of the Tamed Monster's death, as after that, the «Heart» turns into «Remains».