Nymphaeales - Classification

Classification

The Nymphaeales currently includes three families and about 70 to 90 species.

This order was not part of the APG II system's 2003 plant classification (unchanged from the APG system of 1998), which instead had a broadly circumscribed family Nymphaeaceae (including Cabombaceae) unplaced in any order. The APG III system did separate Cabombaceae from Nymphaeaceae and placed them in the order Nymphaeales together with Hydatellaceae. This Hydatellaceae was placed among the monocots in previous systems, but a 2007 study found that the family belongs to Nymphaeales.

Some earlier systems, such as Cronquist's system of 1981, often included the Ceratophyllaceae and Nelumbonaceae in the Nymphaeales. Although, the Takhtajan system of 1980 separated the Nelumbonales, the new order was retained alongside the Nymphaeales in the superorder Nymphaeanae.

The Cronquist system placed the Nymphaeales in subclass Magnoliidae, in class Magnoliopsida . In addition, Cronquist included the Ceratophyllaceae and split the family Barclayaceae from the Nymphaeaceae. Under the APG II system, the family Cambombaceae was included within the Nymphaeaceae, but could optionally be recognized separately. As of APG III, the two families are recognized separately.

The Dahlgren system placed Nymphaeales together with the Piperales in superorder Nymphaeanae, within subclass Magnoliideae (dicotyledons). Thorne's 1992 system (and 2000 revision) placed Nymphaeales as the sole order in the superorder Nymphaeanae within subclass Magnoliideae (=dicotyledons).