A subclass of the class Liliopsida (monocotyledons) of the division Magnoliophyta (Angiospermae), the flowering plants, consisting of 2 orders (Liliales and Orchidales), 19 families, and about 25,000 species. The Liliidae are syncarpous monocotyledons with both the sepals and the petals usually petaloid. The seeds are either nonendospermous or have an endosperm with various sorts of reserve foods such as cellulose, fats or protein, and only seldom starch. The stomates are without subsidiary cells or, in a few small families, have two subsidiary cells. The pollen is binucleate. The vast majority of the species have the vessels chiefly or wholly confined to the roots. The flowers generally have well-developed nectaries, and pollination is usually by insects or other animals.