ABSTRACT
The genus Xanthorrhoea is a member of the family Xanthorrhoeaceae (Hutch.) but is closely aligned to the Liliaceae, having been previously included in that family by Engler and Prantl. 10 Dahlgren and Clifford 8 consider the gems to be the single member of the monogeneric family Xanthorrhoeaceae, while in the recent Flora of Australia, 3 it is one of ten genera in that family, and contains 28 species. Xanthorrhoea is endemic to Australia, and ranges from eastern to southern to southwestern Australia, with the exception of a large desert species (X. thorntonii Tate) found in isolated areas in central Australia. The genus occupies a variety of habitats mostly in areas of annual rainfall greater than or equal to 25 cm.
