Depending upon the authority, there are 80 to 110 species of Lilium. Horticulturally, lilies are separated into nine divisions depending upon origin and care. Species of lilies and all of their natural forms are placed in Division IX. Oriental lilies are in Division VII; they are hybrids involving two Division IX lilies—the golden rayed lily (Lilium auratum) and the Japanese lily (Lilium speciosum).
Botanically, lily species are separated into sections. The two parents, the golden rayed and the Japanese, are placed in Section Archelirion, “chief of lilies”. And rightly so, the flowers are outward facing and wondrously fragrant. Consequently, the Oriental hybrids have magnificent air about them.
(Compiled from: Hortus Third, Staff L.H. Bailey Hortorium, NY State College of Agriculture and Life Sciences, Cornell University, Macmillan, NY, 1976 and A-Z Encyclopedia of Garden Plants, C. Brickell and J.D. Zuk, eds, American Horticultural Society, DK Publishing, NY, 1997)