Nymphaeaceae - Classification

Classification

Nymphaeaceae has been investigated systematically for decades because of the belief that they represent one of the earliest groups of angiosperms. Its position has been somewhat doubtful as the anatomy of these plants is more close to that of monocotyledons, while the venation of the leaves would indicate that they are dicotyledons. Nymphaeaceae is placed in the order Nymphaeales, which is the second diverging group of angiosperms after Amborella in the APG III-classification.

Nymphaeaceae is a small family of three to six genera: Barclaya, Euryale, Nuphar, Nymphaea, Ondinea and Victoria. The genus Barclaya is sometimes given rank as its own family, Barclayaceae, on the basis of an extended perianth tube (combined sepals and petals) arising from the top of the ovary and by stamens that are joined basally. However. molecular phylogenetic work includes it in Nymphaeaceae. The genus Ondinea has recently been shown to be a morphologically aberrant species of Nymphaea, and should be included in this genus. The genera Euryale, of far east Asia, and VIctoria, from South America, are closely related despite their geographic distance, but their relationship toward Nymphaea need further studies.

The sacred lotus was once thought to be a water-lily, but is now recognized to be a highly modified eudicot in its own family Nelumbonaceae of the order Proteales.