Any plant of the genus Hemerocallis, in the family Hemerocallidaceae, consisting of about 15 species of perennial herbaceous plants distributed from central Europe to eastern Asia. Members have long-stalked clusters of funnel- or bell-shaped flowers that range in colour from yellow to red and are each short-lived (hence day lily). Daylilies have fleshy roots and narrow, sword-shaped leaves that are grouped at the base of the plant. The fruit is a capsule. Some species are cultivated as ornamentals or for their edible flowers and buds.