Nelumbo

Nelumbo
Temporal range: Cretaceous–Recent
N. nucifera (sacred lotus)
Scientific classification
Kingdom: Plantae
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Nelumbonaceae
Genus: Nelumbo
Adans.
Species

Nelumbo is a genus of aquatic plants with large, showy flowers. Members are commonly called lotus, though "lotus" is a name also applied to various other plants and plant groups, including the unrelated genus Lotus. Members outwardly resemble those in the family Nymphaeaceae ("water lilies"), but Nelumbo is actually very distant to Nymphaeaceae. "Nelumbo" is derived from the Sinhalese word Sinhalese: නෙළුම් neḷum, the name for the lotus Nelumbo nucifera.[1]

There are only two known living species of lotus; Nelumbo nucifera is native to Asia and is better-known. It is commonly cultivated; it is eaten and used in traditional Chinese medicine. This species is the floral emblem of both India and Vietnam.

The other lotus is Nelumbo lutea and is native to North America and the Caribbean. Horticultural hybrids have been produced between these two allopatric species.

There are several fossil species known from Cretaceous, Paleogene and Neogene aged strata throughout Eurasia and North America.

Species

N. lutea (American lotus)
Nelumbo 'Mrs. Perry D. Slocum'- Dried seed pod
Lotus in lake, showing leaves, buds, flowers, seed heads

Extant species

Fossil species

Classification

There is residual disagreement over which family the genus should be placed in. Traditional classification systems recognized Nelumbo as part of the Nymphaeaceae, but traditional taxonomists were likely misled by convergent evolution associated with an evolutionary shift from a terrestrial to an aquatic lifestyle. In the older classification systems it was recognized under the biological order Nymphaeales or Nelumbonales. Nelumbo is currently recognized as a only living genus in Nelumbonaceae, one of several distinctive families in the eudicot order of the Proteales. Its closest living relatives, the (Proteaceae and Platanaceae), are shrubs or trees.

The leaves of Nelumbo can be distinguished from those of genera in the Nymphaeaceae as they are peltate, that is they have fully circular leaves. Nymphaea, on the other hand, has a single characteristic notch from the edge in to the center of the lily pad. The seedpod of Nelumbo is very distinctive.

APG

Foliage of Nelumbo nucifera: an example of the lotus effect after rain.

The APG IV system of 2016, recognizes Nelumbonaceae as a distinct family and places it in the order Proteales in the eudicot clade, as do the earlier APG III and APG II systems.[4]

Earlier classification systems

The Cronquist system of 1981 recognizes the family but places it in the water lily order Nymphaeales. The Dahlgren system of 1985 and Thorne system of 1992 both recognize the family and place it in its own order, Nelumbonales.

Characteristics

Superhydrophobicity

The leaves of nelumbo are highly water-repellent (i.e. they exhibit ultrahydrophobicity) and have given the name to what is called the lotus effect.[5]

Thermoregulation

Nelumbo nucifera regulates its temperature in order to benefit insect pollinators. When the plant flowers, it heats its blossoms to above 30 °C (86 °F) for as long as four days even when the air is as cool as 10 °C (50 °F). The heat releases an aroma that attracts certain insects, which fly into the flower to feed on nectar and pollen. According to Roger Seymour and Paul Schultze-Motel of Australia’s University of Adelaide, the heat also rewards insects with a stable environment that enhances their ability to eat, mate, and prepare for flight.[6]

Cultural significance

The sacred lotus, N. nucifera, is sacred in both Hinduism and Buddhism.[2]

References

  1. Hyam, R. & Pankhurst, R.J. (1995). Plants and their names : a concise dictionary. Oxford: Oxford University Press. ISBN 978-0-19-866189-4.
  2. 1 2 "Nelumbo nucifera (sacred lotus)". Kew. Retrieved 26 July 2015.
  3. Hickey, Leo (1977). Stratigraphy and Paleobotany of the Golden Valley Formation (Early Tertiary) of Western North Dakota. Boulder, Colorado: Geological Society of America. pp. 110 & Plate 5. ISBN 0-8137-1150-9.
  4. Angiosperm Phylogeny Group (2016). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG IV" (PDF). Botanical Journal of the Linnean Society. 181 (1): 1–20. ISSN 0024-4074. doi:10.1111/boj.12385.
  5. Darmanin, Thierry; Guittard, Frédéric (1 June 2015). "Superhydrophobic and superoleophobic properties in nature". Materials Today. 18 (5): 273–285. doi:10.1016/j.mattod.2015.01.001.
  6. "Heat of Lotus Attracts Insects And Scientists". New York Times. 1996-10-01.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.