Asphodelaceae

Asphodelaceae is a family of flowering plants in the order Asparagales. Such a family has been recognized by most taxonomists, but the circumscription has varied widely. In its current circumscription in the APG IV system, it includes about 40 genera and 900 known species. The type genus is Asphodelus. As defined by the Angiosperm Phylogeny Group in 2009 (the APG III system), the family consisted of three subfamilies: Asphodeloideae, Hemerocallidoideae and Xanthorrhoeoideae. Earlier these three had been treated as separate families. The family Asphodelaceae was made a nomen conservandum (conserved name) in 2017. Previously, the name Xanthorrhoeaceae had priority.. This was anticipated in the APG IV family lists. The family has a wide but scattered distribution throughout the tropics and temperate zones. Many of the species are cultivated as ornamentals. A few are grown commercially for cut flowers. Two species of Aloe are grown for their leaf sap, which has medicinal and cosmetic uses. Xanthorrhoea is endemic to Australia. In some of the older systems of plant taxonomy, such as the Cronquist system, the plants that now form the family Dasypogonaceae were also considered to belong to this family. Molecular phylogenetic studies have shown that Dasypogonaceae belongs to the commelinids and is therefore not even in the same order as Asphodelaceae. Members of the Asphodelaceae are diverse, with few characters uniting the three subfamilies currently recognized. The presence of anthraquinones is one common character. The flowers (the inflorescence) are typically borne on a leafless stalk (scape) which arises from a basal rosette of leaves. The individual flowers have jointed stalks (pedicels). A disk of woody tissue (a hypostase) is present at the base of the ovule. The subfamily Xanthorrhoeoideae contains only the genus Xanthorrhoea, native to Australia. Plants typically develop thick woody stems; the flowers are arranged in a dense spike. Members of the subfamily Asphodeloideae are often leaf succulents, such as aloes and haworthias, although the subfamily also includes ornamental perennials such as red hot pokers (Kniphofia). Members of the subfamily Hemerocallidoideae are varied in habit. Daylilies (Hemerocallis) are one of the widely grown members of this subfamily. The order Asparagales can be divided into a basal paraphyletic group, the 'lower Asparagales', which includes the Asphodelaceae as defined here, and a well-supported monophyletic group of 'core Asparagales', comprising Amaryllidaceae sensu lato and Asparagaceae sensu lato. Three separate families were at one time recognized (e.g. in the first APG system of 1998): Asphodelaceae, Hemerocallidaceae and Xanthorrhoeaceae. Molecular phylogenetic studies have shown that the three are closely related, although Rudall considered that the combination into a single clade was not supported by morphological analysis. The most recent APG classification, the APG IV system of 2016, places the three former families into a single family, the Asphodelaceae sensu lato. The former families are treated as three subfamilies: Asphodeloideae, Hemerocallidoideae and Xanthorrhoeoideae.