Two Passiflora are attainable in game, the first is obtained in Karst Castle after meeting up with a friend, the second is the reward for delivering twenty Ivory Bugs to the rabbit girl in the garden.
Just before the second save-point in Karst Castle the player finds the Knightess critically injured. When spoken to, she asks that the player put her out of her misery. Selecting yes will trigger a cutscene and remove her body, with the Passiflora left where she was. Selecting no will result in the Passiflora not immediately spawning, one would have to exit and re-enter the room to have it spawn, it sits in front of her body.
See Ivory Bug.
The Passiflora is a powerful healing item, it will fully heal the priestess when used.
Using it in a boss fight, even when at full health, will make the player unable to attain the no-hit boss item.