Nymphaeales

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Nymphaeales is an order of flowering plants that lives in water. It includes three families: Hydatellaceae, Cabombaceae, and Nymphaeaceae (water lilies).

What they are like
- They are aquatic or very aquatic plants, mostly rhizomatous (with roots in the bottom) or tuberous.
- Leaves can be submerged, floating on the surface, or rising above the water.
- Flowers are often large and showy.
- Plants can be bisexual and may be monoecious (both sexes on one plant) or dioecious (separate male and female plants).

How many species
- There are about 70 to 90 species in roughly 11 genera. Scientists sometimes disagree on the exact numbers, especially in the genus Nymphaea.

Fossil record and age
- The group reaches back to the Cretaceous period. The crown group is estimated to be around 112 million years old, though some researchers debate this.
- Earlier or related members have been found as fossils in places like Portugal, Brazil, Jordan, Antarctica, and China. Notable early forms include Monetianthus and Jaguariba, with others such as Archaefructus possibly related.

Taxonomy and classification history
- Modern classification (APG system) places Hydatellaceae, Cabombaceae, and Nymphaeaceae all in the order Nymphaeales.
- Hydatellaceae was once thought to be a monocot, but a 2007 study placed it with Nymphaeales.
- In older systems, the families were arranged differently, and some classifications varied on whether Cabombaceae was kept separate or included with Nymphaeaceae.
- APG IV currently recognizes all three families within Nymphaeales.

Some well-known members
- Nymphaea lotus (a water lily)
- Nuphar lutea (yellow water-lily)
- Victoria amazonica (giant water-lily)
- Euryale ferox
- Cabomba aquatica
- Brasenia schreberi

In short, Nymphaeales are an ancient, water-dwelling group of flowering plants notable for their aquatic lifestyle, large flowers, and a classification history that has evolved with new scientific findings.