Nelumbonaceae, sometimes called the sacred lotus family, is a family of flowering plants, including the single genus Nelumbo with two species, N. lutea (North America) and N. nucifera (widespread in tropical Asia). While in the past, members of the family have been included in the waterlily family, Nymphaeaceae, it is now widely accepted, following molecular studies, that the Nelumbonaceae are actually an example of convergent evolution and are highly modified eudicots belonging to the order Proteales, their closest living relatives being the plane trees (Platanaceae) and Proteaceae. The APG IV system of 2016 (unchanged from the earlier APG system of 1998, the APG II system of 2003 and the APG III system of 2009) places the family in the order Proteales, in the clade eudicots. The family consists of aquatic plants, extant Nelumbo are native to North America and Asia (and perhaps some adjacent areas, but widely cultivated). At least four other genera, Nelumbites, Exnelumbites, Paleonelumbo, and Nelumbago, are known from fossils. The Cronquist system, of 1981, also recognized this family, but placed it in order Nymphaeales in subclass Magnoliidae in class Magnoliopsida (=dicotyledons), based on gross morphological similarities. The Dahlgren system and Thorne system (1992) also recognized this family and placed it in its own order, Nelumbonales, in superorder Magnolianae in subclass Magnoliidae (=dicotyledons).