Let's start with the daylily. The easiest way to distinguish the daylily from its cousins is by examining its roots and leaves. Most other Liliaceae grow from scaly bulbs. The leaves of a daylily arise from its crown and are long, slender and grass-like. They have a central rib and are arranged opposite each other on the crown and a single plant is often referred to as a clump.
Some varieties have double blooms which means they have more than six segments.
The bloom habits include diurnal which is the normal type, beginning in the early morning and lasting until the evening, nocturnal which open late in the afternoon, remain open all night and close the following morning and extended where individual blooms remain open at least 16 hours. Oriental and asiatic lilies also are in the Liliaceae family and therefore true lilies. Both are in the genus Lilium, a large and varied group of plants which grow from bulbs with overlapping scales that lack the papery brown covering of bulbs such as tulips and narcissus. The flowers form in terminal clusters of 3-75 blooms, depending on the variety. Hybrid Lilium are separated into eight divisions by the American Lily Society based on the shape and position of their flowers and on their hybrid origin.