Nymphaeales

Key takeaways

Nymphaeales belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Nymphaeales to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Nymphaeales from memory before moving on to harder problems.

Reference excerpt

The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae (water lilies). It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants. At least 10 morphological characters unite the Nymphaeales. One of the traits is the absence of a vascular cambium, which is required to produce both xylem (wood) and phloem, which therefore are missing. Molecular synapomorphies are also known. The Plant List, created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden recognizes about 70 species in 11 genera within the order, but a phylogenetic study of the genus Nymphaea implies that the number of species could be more than 90. The difference in species numbers is due almost entirely to the difficulty of delineating species in the genus Nymphaea. Most of the species are rhizomatous aquatic herbs with a broad leaf base and large, showy flowers.

Description

Vegetative characteristics Nymphaeales are rhizomatous or tuberous, aquatic or sub-aquatic, annual or perennial herbs. The leaves are submerged, floating, or emerged. The floating leaves are 1 mm to 3.2 m wide.

Generative characteristics The plants are bisexual, monoecious or dioecious. The female gametophyte is the Schisandra-type, consisting of four cells.

Fossils The fossil record consists especially of seeds, but also pollen, stems, leaves, and flowers. It extends back to the Cretaceous. The crown group of the Nymphaeales has been estimated to be about 112 million years old. Some have suggested that this age might be too old. A basal member of Nymphaeales, Monetianthus, is known from Early Cretaceous Portugal. A fossil member of the Nympheaceae is Jaguariba from the Early Cretaceous of Brazil. Several Cretaceous-age Cabombaceae genera are also known, including Scutifolium from Jordan, Pluricarpellatia from Brazil, and Brasenites from Kansas. The fossil genus Notonuphar, thought to be a close relative of the modern Nuphar, is known from Eocene-aged sediments from Seymour Island, Antarctica. The genus Brasipelta Krassilov has been described from the late Cretaceous of Israel. The aquatic plant fossil Archaefructus from the Early Cretaceous of Liaoning, China possibly also belongs to this group.

Classification The Nymphaeales currently include 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 the Cabombaceae from the Nymphaeaceae and placed them in the order Nymphaeales together with the Hydatellaceae. The family Hydatellaceae was placed among the monocots in previous systems, but a 2007 study found that the family belongs to the Nymphaeales. In the APG IV system, Hydatellaceae, Cabombaceae and Nymphaeaceae are the three families included in the 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 [=dicotyledons]. In addition, Cronquist included the Ceratophyllaceae and split the family Barclayaceae from the Nymphaeaceae. Under the APG II system, the family Cabombaceae 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 the Nymphaeales with the Piperales in superorder Nymphaeanae, within subclass Magnoliideae (dicotyledons). Thorne's 1992 system (and 2000 revision) placed the Nymphaeales as the sole order in the superorder Nymphaeanae within subclass Magnoliideae (=dicotyledons).

References

Further reading Michael G. Simpson. Plant Systematics. Elsevier Academic Press. 2006. Thomas N. Taylor, Edith L. Taylor, and Michael Krings. 2008. Paleobotany: The Biology and Evolution of Fossil Plants, Second Edition. Academic Press (an imprint of Elsevier): Burlington MA, USA. ISBN 978-0-12-373972-8

External links Nymphaeales At: Angiosperm Phylogeny Website At: botanical databases At: Plant Science At: Missouri Botanical Garden Data related to Nymphaeales at Wikispecies

Illustrations

Worked examples

Example 1 — a first encounter with Nymphaeales

Start with the simplest possible case. Write down what Nymphaeales claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Nymphaeales before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Nymphaeales ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Nymphaeales

In research: Nymphaeales appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Nymphaeales in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Nymphaeales is common in secondary-school and first-year university syllabi. It links to neighbouring topics Angiosperm orders, Early Cretaceous plants, Extant Early Cretaceous first appearances, so understanding it makes those chapters shorter.
In everyday life: Look for Nymphaeales outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Nymphaeales in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Nymphaeales means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Nymphaeales out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Nymphaeales in simple terms?

The Nymphaeales are an order of flowering plants, consisting of three families of aquatic plants, the Hydatellaceae, the Cabombaceae, and the Nymphaeaceae (water lilies). It is one of the three orders of basal angiosperms, an early-diverging grade of flowering plants.

Why does Nymphaeales matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Nymphaeales?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Nymphaeales.