Liliidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used (there are many such systems); the only requirement being that it includes the family Liliaceae. Wikipedia has adopted the APG II system which does not use formal botanical names above the rank of order. A botanical name is a formal name conforming to the ICBN. As with its zoological and bacterial equivalents it may also be called a scientific name. Botanical names may be in one part (genus and above), two parts (species) or three parts (below the rank of species). ... In botanical nomenclature, a taxon is usually assigned to a rank in a hierarchy. ... In biology, a subclass is one level below a class. ... Genera Calochortus Cardiocrinum Clintonia Erythronium Fritillaria Gagea Korolkowia Lilium Lloydia Nomocharis Notholirion Scoliopus Streptopus Tricyrtis Tulipa The Liliaceae, or the Lily Family, is an important family of monocotyledons that includes a great number of ornamental flowers as well as several important agricultural crops; the onion has traditionally been classified here... A botanical name is a formal name conforming to the ICBN. As with its zoological and bacterial equivalents it may also be called a scientific name. Botanical names may be in one part (genus and above), two parts (species) or three parts (below the rank of species). ... In botanical nomenclature, a taxon is usually assigned to a rank in a hierarchy. ...

• The most prominent use of this name is made by the Dahlgren system and Thorne system, where this subclass comprises the monocotyledons (in APG II these are the monocots ).
• In the Cronquist system the monocotyledons are the class Liliopsida: this subclass Liliidae includes two orders, Liliales and Orchidales.