The passion flowers or passion vines (Passiflora) are a of about 500 species of flowering plants. The incarnata, involucrata, alata, edulis, quadrangularis, and caerulea species are known to be psychoactive. Damiana is sometimes consider a part of the genus, however is never referred to colloquially as "passion flower".
Passion flower is an extremely mild MAOi. If used in extremely large doses, be careful when mixing or taking with prescription medication.