Nelumbo

Nelumbo is a genus of aquatic plants with large, showy flowers. Members are commonly called lotus, though 'lotus' is a name also applied to various other plants and plant groups, including the unrelated genus Lotus. Members outwardly resemble those in the family Nymphaeaceae ('water lilies'), but Nelumbo is actually very distant to Nymphaeaceae. 'Nelumbo' is derived from the Sinhalese word Sinhala: නෙළුම් neḷum, the name for the lotus Nelumbo nucifera. There are only two known living species of lotus; N. nucifera is native to Asia and is better-known. It is commonly cultivated; it is eaten and used in traditional Chinese medicine. This species is the floral emblem of both India and Vietnam. The other lotus is Nelumbo lutea and is native to North America and the Caribbean. Horticultural hybrids have been produced between these two allopatric species. There are several fossil species known from Cretaceous, Paleogene and Neogene aged strata throughout Eurasia and North America. There is residual disagreement over which family the genus should be placed in. Traditional classification systems recognized Nelumbo as part of the Nymphaeaceae, but traditional taxonomists were likely misled by convergent evolution associated with an evolutionary shift from a terrestrial to an aquatic lifestyle. In the older classification systems it was recognized under the biological order Nymphaeales or Nelumbonales. Nelumbo is currently recognized as a only living genus in Nelumbonaceae, one of several distinctive families in the eudicot order of the Proteales. Its closest living relatives, the (Proteaceae and Platanaceae), are shrubs or trees. The leaves of Nelumbo can be distinguished from those of genera in the Nymphaeaceae as they are peltate, that is they have fully circular leaves. Nymphaea, on the other hand, has a single characteristic notch from the edge in to the center of the lily pad. The seedpod of Nelumbo is very distinctive. The APG IV system of 2016, recognizes Nelumbonaceae as a distinct family and places it in the order Proteales in the eudicot clade, as do the earlier APG III and APG II systems. The Cronquist system of 1981 recognizes the family but places it in the water lily order Nymphaeales. The Dahlgren system of 1985 and Thorne system of 1992 both recognize the family and place it in its own order, Nelumbonales. The USDA still classifies the lotus family within the water lily order.