Codariocalyx motorius

{{Short description|Species of legume}}

{{Speciesbox

|image = Thozhukanni.JPG

|image_caption =

|genus = Codariocalyx

|species = motorius

|authority = (Houtt.) H. Ohashi

|synonyms = * Codariocalyx gyrans (L. f.) Hassk.

• Desmodium gyrans (L.) DC.
• Desmodium gyrans (L. f.) DC.
• Desmodium gyrans (L.) DC. var. roylei (Wight & Arn.)Baker
• Desmodium motorium (Houtt.) Merr.
• Desmodium roylei Wight & Arn.
• Hedysarum gyrans L. f.
• Hedysarum motorium Houtt.
• Hedysarum motorius Houtt.
• Meibomia gyrans (L. f.) Kuntze

}}

Codariocalyx motorius (though often placed in Desmodium{{cite web |work=International Legume Database & Information Service |url=http://www.ildis.org/LegumeWeb?version~10.01&LegumeWeb&tno~15832&genus~Codariocalyx&species~motorius |title=Codariocalyx motorius |date=November 2005 |accessdate=December 18, 2007}}), known as the telegraph plant, dancing plant, or semaphore plant, is a tropical Asian shrub in the pea family (Fabaceae), one of a few plants capable of rapid movement; others include Mimosa pudica, the venus flytrap and Utricularia. The motion occurs in daylight hours when the temperature is above {{convert|72|F|C}}. Many sources claim that the two leaflets move on a common axis (like the blades of a kayak paddle) even though there is no rigid connection between them.{{cite book | last1= Chittendon | first1= Fred J. | last2= Synge | first2= Patrick M. | date= 1965 | title= The Royal Hort. Soc. Dictionary of Gardening - Volume 2 | location= Oxford, Eng. | publisher= Clarendon Press | page=663 }}

It is widely distributed throughout Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Taiwan, Thailand and Vietnam. It can even be found on the Society Islands, a remote chain of islands in the South Pacific. It produces small, purple flowers which turn orange with time.{{cite book | last= Allen | first= O.N. and Ethel K. | date= 1981 | title= The Leguminosae - A Sourcebook of Characteristics, Uses and Nodulation | location= Madison, Wisconsin | publisher= Univ. of Wisc. Press | page= 174 | ISBN= 0-299- 08400-0 }}

This plant has small, lateral leaflets which move at speeds rapid enough to be perceivable with the naked eye. This is possibly a strategy to maximise light by tracking the sun.{{Cite web|url=http://florawww.eeb.uconn.edu/199800023.html|title=Codariocalyx motorius (Houtt.) H.Ohashi|date=July 2018|website=University of Connecticut}}{{Cite web|url=http://casadeflores.es/codariocalyx-motorius-desmodium-gyrans-planta-baile-p-57.html|title=CODARIOCALYX MOTORIUS (DESMODIUM GYRANS: LA PLANTA DE BAILE)|date=May 2013|website=Casa de Flores|access-date=2018-07-25|archive-url=https://web.archive.org/web/20180725063717/http://casadeflores.es/codariocalyx-motorius-desmodium-gyrans-planta-baile-p-57.html|archive-date=2018-07-25|url-status=dead}} Each leaf is equipped with a hinge that permits it to be moved to receive more sunlight, but the weight of these leaves means the plant must expend a lot of energy in moving it. To optimise its movement, each large leaf has two small leaflets at its base. These move constantly along an elliptical path, sampling the intensity of sunlight, and directing the large leaf to the area of most intensity. Another hypothesis has been offered that the rapid movements are intended to deter potential predators.Simcha Lev-Yadun. "The enigmatic fast leaflet rotation in Desmodium motorium: Butterfly mimicry for defense?" Plant Signaling & Behavior, 2013. "[http://www.tandfonline.com/doi/pdf/10.4161/psb.24473] It has also been suggested that these movements may be a form of butterfly mimicry to prevent the laying of butterfly eggs on the plant's leaves.{{Cite journal|last=Lev-Yadun|first=Simcha|date=2013-06-01|title=The enigmatic fast leaflet rotation in Desmodium motorium|journal=Plant Signaling & Behavior|volume=8|issue=6|pages=e24473|doi=10.4161/psb.24473|pmc=3908938|pmid=23603964|bibcode=2013PlSiB...8E4473L }}

The common name is due to the rotation of the leaflets with a period of about three to five minutes; this was likened to a semaphore telegraph, a structure with adjustable paddles that could be seen from a distance, the position of which conveyed a message in semaphore,{{Cite web|url=https://sites.evergreen.edu/plantchemeco/codariocalyx-motorius-mystery-of-the-dancing-plant/|title=Mystery of the Dancing Plant: Perhaps the Most Mystical Pea Plant since Jack's Magic Beanstalk.|website=The Evergreen State College}}{{Cite web|url=https://www.californiacarnivores.com/blogs/cal-carn-blog/75624069-the-telegraph-plant|title=The Telegraph Plant by Peter D'Amato|last=D'Amato|first=Peter|date=January 2016|website=California Carnivores|access-date=2018-07-25|archive-date=2019-03-18|archive-url=https://web.archive.org/web/20190318060705/https://www.californiacarnivores.com/blogs/cal-carn-blog/75624069-the-telegraph-plant|url-status=dead}}{{Cite web|url=https://funflowerfacts.com/2013/07/16/weird-and-unusual-plant-the-dancing-plant-codariocalyx-motorius/|title=Weird and Unusual Plant: The Dancing Plant (Codariocalyx Motorius)|last=Lowry|first=Connor|date=July 2013|website=fun flower facts|access-date=2018-07-25|archive-url=https://web.archive.org/web/20180725063509/https://funflowerfacts.com/2013/07/16/weird-and-unusual-plant-the-dancing-plant-codariocalyx-motorius/|archive-date=2018-07-25|url-status=dead}} hence the common names.

File:Codariocalyx motorius Taub39.png

The plant is described in detail in Charles Darwin's 1880 The Power of Movement in Plants.