Paris quadrifolia, the herb-paris or true lover's knot, is a Eurasian species of flowering plant in the family Melanthiaceae, although authorities formerly regarded it as part of the Liliaceae family. It is related to Trillium, with which it can be confused. Trillium, however, is generally 3-merous (3 leaves per whorl, 3 petals etc.), whereas Paris quadrifolia is 4-merous.