The scientific name for daylily is Hemerocallis, most recently considered to belong in the plant family Hemerocallidaceae. Previously, many older works placed daylilies in the Lily family, Liliaceae. Notice that the preferred spelling is “daylily” as one word. Many dictionaries spell it as two words. The word Hemerocallis is derived from two Greek words meaning “beauty” and “day,” referring to the fact that each flower lasts only one day. To make up for this, there are many flower buds on each daylily flower stalk, and many stalks in each clump of plants, so, the flowering period of a clump is usually several weeks long. And, many cultivars have more than one flowering period.