Nymphaeales Explained

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.^[1] 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.^[2] 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,^[3] but a phylogenetic study of the genus Nymphaea implies that the number of species could be more than 90.^[4] The difference in species numbers is due almost entirely to the difficulty of delineating species in the genus Nymphaea.

All of the species are rhizomatous aquatic herbs with a broad leaf base and large, showy flowers.

Fossils

The fossil record consists especially of seeds, but also pollen, stems, leaves, and flowers. It extends back to the Cretaceous.^{[5] [6]} The crown group of the Nymphaeales has been estimated to be about 112 million years old.^[7] Some have suggested that this age might be too old.^[8]

A basal member of Nymphaeales, Monetianthus, is known from Early Cretaceous Portugal.^[9] 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.^[10] The fossil genus Notonuphar, thought to be a close relative of the modern Nuphar, is known from Eocene-aged sediments from Seymour Island, Antarctica.^[11] The aquatic plant fossil Archaefructus from the Early Cretaceous of Liaoning, China possibly also belongs to this group.^[12]

Classification

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

order Nymphaeales Cabombaceae Brasenia (one species) Cabomba (five species) Hydatellaceae Trithuria (12 species) Nymphaeaceae Barclaya (three or four species) Euryale (one species) Nuphar (10-12 species) Nymphaea (35-50 species) Victoria (three species)
The classification of Nymphaeales and phylogeny within the flowering plants, as of APG III (2009).

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.^[13] In the APG IV system, Hydatellaceae, Cabombaceae and Nymphaeaceae are the three families included in the Nymphaeales.^[14]

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).

APG III system^[15]
Nymphaeales!style="background:lightgreen" align="center" width="160px"

Takhtajan system^[16] Nymphaeales	Cronquist system^[17] Nymphaeales	Dahlgren system^[18] Nymphaeales	Thorne system (1992)^[19] & (2000)^[20] Nymphaeales
Hydatellaceae	among monocots, as Hydatellales
Cabombaceae	Cabombaceae Brasenia, Cabomba	Cabombaceae Brasenia, Cabomba	Cabombaceae	Cabombaceae Brasenia, Cabomba
Nymphaeaceae	Nymphaeaceae subf. Barclayoideae, Euryaloideae, Nymphaeoideae	Barclayaceae Barclaya	Nymphaeaceae	Nymphaeaceae Barclaya, Euryale, Nuphar, Nymphaea, Ondinea, Victoria
		Nymphaeaceae Euryale, Nuphar, Nymphaea, Ondinea, Victoria
sister to eudicot clade	Ceratophyllaceae	Ceratophyllaceae	Ceratophyllaceae	in Ranunculanae
in Proteales	in Nelumbonales	Nelumbonaceae	in Magnolianae

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.

External links

• Nymphaeales

At: Angiosperm Phylogeny Website At: botanical databases At: Plant Science At: Missouri Botanical Garden

Notes and References

1. Peter F. Stevens. 2001 onwards. Angiosperm Phylogeny Website At: Missouri Botanical Garden Website. (see External links below).
2. https://www.biorxiv.org/content/10.1101/2019.12.18.881573v1.full Water lily (Nymphaea thermarum) genome reveals variable genomic signatures of ancient vascular cambium losses | bioRxiv
3. The Plant List (website). 2010. (See External links below.)
4. Borsch . Thomas . Löhne . Cornelia . Samba Mbaye . Mame . Wiersema . John H. . 2011 . Towards a complete species tree of Nymphaea: shedding further light on subg. Brachyceras and its relationships to the Australian water-lilies . . 13 . 1–2. 193–217 . 10.7751/telopea20116014 . free .
5. Web site: Nymphaeales: Fossil Record . University of California Museum of Paleontology.
6. . 410 . 357–360 . 15 March 2001 . Fossil evidence of water lilies (Nymphaeales) in the Early Cretaceous . Else Marie Friis, Kaj Raunsgaard Pedersen and Peter R. Crane . 10.1038/35066557 . 11268209 . 6826 . 2001Natur.410..357F . 205014988 .
7. Magallón . Susana . Castillo . Amanda . 2009 . Angiosperm diversification through time . . 96 . 1. 349–365 . 10.3732/ajb.0800060 . 21628193.
8. Bell . Charles D. . Soltis . Douglas E. . Douglas E. Soltis . Soltis . Pamela S. . Pamela S. Soltis. 2010 . The age and diversification of the angiosperms re-revisited . American Journal of Botany . 97 . 8. 1296–1303 . 10.3732/ajb.0900346 . 21616882. 207613985 .
9. Friis . Else Marie. Pedersen. Kaj Raunsgaard. von Balthazar. Maria . Grimm. Guido W.. Crane . Peter R.. May 2009 . Monetianthus mirus gen. et sp. nov., a Nymphaealean Flower from the Early Cretaceous of Portugal . International Journal of Plant Sciences . en . 170 . 8 . 1086–1101 . 10.1086/605120 . 84760466 . 1058-5893.
10. Taylor . David Winship . Gee . Carole T. . 1 October 2014 . Phylogenetic Analysis of Fossil Water Lilies Based on Leaf Architecture and Vegetative Characters: Testing Phylogenetic Hypotheses from Molecular Studies . Bulletin of the Peabody Museum of Natural History . 55 . 2 . 89–110 . 10.3374/014.055.0208 . 84253809 . 0079-032X.
11. Friis . Else M. . Iglesias . Ari . Reguero . Marcelo A. . Mörs . Thomas . 2017-08-01 . Notonuphar antarctica, an extinct water lily (Nymphaeales) from the Eocene of Antarctica . Plant Systematics and Evolution . en . 303 . 7 . 969–980 . 10.1007/s00606-017-1422-y . 23846066 . 2199-6881. free .
12. The Year in Evolutionary Biology 2008 . June 2008 . . 1133 . 3–25 . 10.1196/annals.1438.005 . 18559813 . Soltis . D. E. . Douglas E. Soltis . Bell . CD . Kim . S . Soltis . PS . Pamela S. Soltis . 1 . https://web.archive.org/web/20090108184520/http://www.annalsnyas.org/cgi/content/abstract/1133/1/3 . 2009-01-08 . 10.1.1.463.7533 . 17688086 .
13. Hydatellaceae identified as a new branch near the base of the angiosperm phylogenetic tree . Nature . 446 . 7133 . 312–5 . 2007 . 17361182 . 10.1038/nature05612 . Saarela . J. M. . Rai . H. S. . Doyle . J. A. . Endress . P. K. . Mathews . S. . Marchant . A. D. . Briggs . B. G. . Graham . S. W. . 2007Natur.446..312S . 4415881 . 1.
14. Angiosperm Phylogeny Group . 2016. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV. Botanical Journal of the Linnean Society. 181. 1. 1–20. 0024-4074. 10.1111/boj.12385. free.
15. . 161 . 105–121 . Angiosperm Phylogeny Group . 2009 . An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III . 10.1111/j.1095-8339.2009.00996.x . 2. free .
16. Takhtajan . Armen L. . 1980 . Outline of the classification of flowering plants (Magnoliophyta) . The Botanical Review . 46 . 3 . 225–359 . 10.1007/BF02861558 . 30764910 .
17. Book: Cronquist, Arthur . 1981 . An Integrated System of Classification of Flowering Plants . registration . New York . Columbia University Press . 978-0-231-03880-5 .
18. Dahlgren . R.M.T. . 1980 . A revised system of classification of angiosperms . Botanical Journal of the Linnean Society . 80 . 2 . 91–124 . 10.1111/j.1095-8339.1980.tb01661.x .
19. Thorne . R. F. . 1992 . Classification and geography of the flowering plants . Botanical Review . 58 . 225–348 . 10.1007/BF02858611 . 3. 40348158 .
20. Thorne . R. F. . 2000 . The classification and geography of the flowering plants: Dicotyledons of the class Angiospermae . Botanical Review . 66 . 4 . 441–647 . 10.1007/BF02869011 . 43430454 .