Chrysanthemum


Chrysanthemums, sometimes abbreviated to mums or chrysanths, are perennial herbaceous flowering plants in the family Asteraceae that bloom in the autumn. They are native to East Asia and northeastern Europe. Most species originate from East Asia, and the center of diversity is in China. Many thousands of horticultural varieties and cultivars exist.

Description

The genus Chrysanthemum consists of perennial herbaceous flowering plants, sometimes subshrubs. The leaves are alternate, divided into leaflets and may be pinnatisect, lobed, or serrate but rarely entire; they are connected to stalks with hairy bases.
The compound inflorescence is an array of several flower heads, or sometimes a solitary head. The head has a base covered in layers of phyllaries. The simple row of ray florets is white, yellow, or red. The disc florets are yellow. Pollen grains are approximately 34 microns.
The fruit is a ribbed achene.

Etymology

The name "chrysanthemum" is derived from the chrysos and anthemon.

Taxonomy

The genus Chrysanthemum was first formally described by Linnaeus in 1753, with 14 species, and hence bears his name as the botanical authority. The genus once included more species, but was split several decades ago into several genera, putting the economically important florist's chrysanthemums in the genus Dendranthema. The naming of these genera has been contentious, but a ruling of the International Botanical Congress in 1999 changed the defining species of the genus to Chrysanthemum indicum, restoring the florist's chrysanthemums to the genus Chrysanthemum.
Genera now separated from Chrysanthemum include Argyranthemum, Glebionis, Leucanthemopsis, Leucanthemum, Rhodanthemum, and Tanacetum.

Species

, Plants of the World Online accepted the following species:
  • Chrysanthemum × aphrodite Kitam.
  • Chrysanthemum arcticum L.
  • Chrysanthemum argyrophyllum Ling
  • Chrysanthemum arisanense Hayata
  • Chrysanthemum bizarre C.Z.Shen
  • Chrysanthemum chalchingolicum Grubov
  • Chrysanthemum chanetii H.Lév.
  • Chrysanthemum crassum Kitam.
  • Chrysanthemum × cuneifolium Kitam.
  • Chrysanthemum dabieshanense Z.X.Fu, A.G.Zhen & Y.P.Ma
  • Chrysanthemum dichrum H.Ohashi & Yonek.
  • Chrysanthemum foliaceum J.M.Wang & Y.T.Hou
  • Chrysanthemum glabriusculum Hand.-Mazz.
  • Chrysanthemum horaimontanum Masam.
  • Chrysanthemum hypargyreum Diels
  • Chrysanthemum indicum L.
  • Chrysanthemum integrifolium Richardson
  • Chrysanthemum japonense Nakai
  • Chrysanthemum lavandulifolium Makino
  • Chrysanthemum × leucanthum Makino
  • Chrysanthemum longibracteatum J.M.Wang & Y.T.Hou
  • Chrysanthemum makinoi Matsum. & Nakai
  • Chrysanthemum maximoviczii Kom.
  • Chrysanthemum × miyatojimense Kitam.
  • Chrysanthemum × morifolium Hemsl.
  • Chrysanthemum morii Hayata
  • Chrysanthemum naktongense Nakai
  • Chrysanthemum nankingense Hand.-Mazz.
  • Chrysanthemum neo-oreastrum C.C.Chang
  • Chrysanthemum ogawae Kitam.
  • Chrysanthemum okiense Kitam.
  • Chrysanthemum oreastrum Hance
  • Chrysanthemum ornatum Hemsl.
  • Chrysanthemum parvifolium C.C.Chang
  • Chrysanthemum potentilloides Hand.-Mazz.
  • Chrysanthemum rhombifolium H.Ohashi & Yonek.
  • Chrysanthemum × shimotomaii Makino
  • Chrysanthemum sinuatum Ledeb.
  • Chrysanthemum vestitum Kitam.
  • Chrysanthemum yantaiense M.Sun & J.T.Chen
  • Chrysanthemum yoshinaganthum Makino
  • Chrysanthemum zawadzkii Herbich
  • Chrysanthemum zhuozishanense L.Q.Zhao & Jie Yang
Former species include:
  • Chrysanthemum carinatum = Ismelia carinata
  • Chrysanthemum cinerariifolium = Tanacetum cinerariifolium
  • Chrysanthemum coccineum = Tanacetum coccineum
  • Chrysanthemum coronarium = Glebionis coronaria
  • Chrysanthemum frutescens = Argyranthemum frutescens
  • Chrysanthemum maximum = Leucanthemum maximum
  • Chrysanthemum pacificum = Ajania pacifica
  • Chrysanthemum segetum = ''Glebionis segetum''

    Ecology

Chrysanthemums start blooming in early autumn. They are a flower associated with the month of November.

Cultivation

Chrysanthemums were first cultivated in China as a flowering herb as far back as the 15th century BCE. Over 500 cultivars had been recorded by 1630. By 2014, it was estimated that there were over 20,000 cultivars in the world and about 7,000 cultivars in China. The plant is renowned as one of the Four Gentlemen in Chinese and East Asian Art. The plant is particularly significant during the Double Ninth Festival.
Chrysanthemum cultivation in Japan began during the Nara and Heian periods and gained popularity in the Edo period. Many flower shapes, colours, and varieties were created. The way the flowers were grown and shaped also developed, and chrysanthemum culture flourished. Various cultivars of chrysanthemums created in the Edo period were characterized by a remarkable variety of flower shapes. They were exported to China from the end of the Edo period, changing the way Chinese chrysanthemum cultivars were grown and their popularity. In addition, from the Meiji period, many cultivars with flowers over in diameter, called the Ogiku style, were created, which influenced the subsequent trend of chrysanthemums. The imperial crest of Japan is a chrysanthemum, and the institution of the monarchy is also called the Chrysanthemum Throne. A number of festivals and shows take place throughout Japan in autumn when the flowers bloom. Chrysanthemum Day is one of the five ancient sacred festivals. It is celebrated on the 9th day of the 9th month. It was started in 910, when the imperial court held its first chrysanthemum show.
Chrysanthemums entered American horticulture in 1798 when Colonel John Stevens imported a cultivated variety known as Dark Purple from England. The introduction was part of an effort to grow attractions within Elysian Fields in Hoboken, New Jersey.

Classification

For horticultural purposes, all Chrysanthemum cultivars are split into 13 divisions based upon flower form, a classification developed by the National Chrysanthemum Society.

Uses

Ornamental uses

Modern cultivated chrysanthemums are usually brighter and more striking than their wild relatives. Many horticultural specimens have been bred to bear many rows of ray florets in a great variety of colors. The flower heads occur in various forms, and can be daisy-like or decorative, like pompons or buttons. This genus contains many hybrids and thousands of cultivars developed for horticultural purposes. In addition to the traditional yellow, other colors are available, such as white, purple, and red. The most important hybrid is Chrysanthemum × morifolium, derived primarily from C. indicum, but also involving other species.
Over 140 cultivars of chrysanthemum have gained the Royal Horticultural Society's Award of Garden Merit.
In Japan, a form of chrysanthemum bonsai was developed over the centuries. The cultivated flower has a lifespan of about 5 years and can be kept in miniature size. A bonsai-like effect can also be created by using pieces of dead wood with the flower growing over the back along the wood, to give the illusion from the front that the a miniature tree blooms in chrysanthemums.

Culinary uses

Yellow or white chrysanthemum flowers of the species C. morifolium are boiled to make a tea in some parts of East Asia. The resulting beverage is known simply as chrysanthemum tea. In Korea, a rice wine flavored with chrysanthemum flowers is called gukhwaju.
Chrysanthemum leaves are steamed or boiled and used as greens, especially in Chinese cuisine. The flowers may be added to dishes such as mixian in broth or thick snakemeat soup to enhance the aroma. They are commonly used in hot pot and stir fries. In Japanese cuisine, small chrysanthemums are used as garnish for sashimi.

Insecticidal uses

is economically important as a natural source of insecticide. The flowers are pulverized, and the active components, called pyrethrins, which occur in the achenes, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. In sublethal doses, they have an insect repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides. They are not persistent, being biodegradable, and also decompose easily on exposure to light. Pyrethroids such as permethrin are synthetic insecticides based on natural pyrethrum. Despite this, chrysanthemum leaves are still a major host for destructive pests, such as leafminer flies including L. trifolii.
Persian powder is an example of industrial product of chrysanthemum insecticide.

Environmental uses

Chrysanthemum plants have been shown to reduce indoor air pollution by the NASA Clean Air Study.

In culture

In some European countries, incurve chrysanthemums symbolize death and are used only for funerals or on graves, while other types carry no such symbolism; similarly, in China, Japan, and Korea of East Asia, white chrysanthemums symbolize adversity, lamentation, and/or grief. In some other countries, they represent honesty. In the United States, the flower is usually regarded as positive and cheerful, with New Orleans as a notable exception.
In the Victorian language of flowers, the chrysanthemum had several meanings. The Chinese chrysanthemum meant cheerfulness, whereas the red chrysanthemum stood for "I Love", while the yellow chrysanthemum symbolized slighted love. The chrysanthemum is also the flower of November.