An order of monocotyledons, the well-known lilies or family Liliaceae of many previous botanists, actually consisting of 9 families and about 1600 species. Liliales are clearly circumscribed in deoxyribonucleic acid (DNA) sequence analyses, but are difficult to define on the basis of morphological characters, resulting in varying family composition in different classifications. Separation of Liliales from the lilylike Asparagales has proved particularly problematic, but they differ in nectary position (septal in Asparagales) and absence of phytomelan, a dark seedcoat pigment present in most families of Asparagales. Nearly all features marking the families of Liliales are micromorphological (for example, perigonal nectaries, nuclear endosperm formation).