Peony

The peony or paeony is a flowering plant in the genus Paeonia, the only genus in the family Paeoniaceae. Peonies are native to Asia, Europe and Western North America. Scientists differ on the number of species that can be distinguished, ranging from 25 to 40, although the current consensus is 33 known species. The relationships between the species need to be further clarified.
Most are herbaceous perennial plants tall, but some are woody shrubs tall. They have compound, deeply lobed leaves and large, often fragrant flowers, in colors ranging from purple and pink to red, white or yellow, in late spring and early summer. The flowers have a short blooming season, usually only 7–10 days.
Peonies are popular garden plants in temperate regions. Herbaceous peonies are also sold as cut flowers on a large scale, although generally only available in late spring and early summer.
Description.
Morphology.
All Paeoniaceae are herbaceous perennials or deciduous shrubs, with thick storage roots and thin roots for gathering water and minerals. Some species are caespitose (tufted), because the crown produces adventitious buds, while others have stolons. They have rather large compound leaves without glands and stipules, and with anomocytic stomata. In the woody species the new growth emerges from scaly buds on the previous flush or from the crown of the rootstock. The large bisexual flowers are mostly single at the end of the stem. In "P. emodi", "P. lactiflora", "P. veitchii" and many of the cultivars these contributed to, few additional flowers develop in the axils of the leaves. Flowers close at night or when the sky is overcast. Each flower is subtended by a number of bracts, that may form a sort of involucre, has 3-7 tough free sepals and mostly 5-8, but occasionally up to 13 free petals. These categories however are intergrading, making it difficult to assign some of them, and the number of these parts may vary. Within are numerous (50–160) free stamens, with anthers fixed at their base to the filaments, and are sagittate in shape, open with longitudal slits at the outer side and free pollen grains which have three slits or pores and consist of two cells. Within the circle of stamens is a more or less prominent, lobed disc, which is presumed not to excrete nectar. Within the disk is a varying number (1-15) of separate carpels, which have a very short style and a decurrent stigma. Each of these develops into a dry fruit (which is called a follicle), which opens with a lengthwise suture and each of which contains one or a few large fleshy seeds. The annual growth is predetermined: if the growing tip of a shoot is removed, no new buds will develop that season.
Phytochemistry.
Over 262 compounds have been obtained so far from the plants of Paeoniaceae. These include monoterpenoid glucosides, flavonoids, tannins, stilbenoids, triterpenoids, steroids, paeonols, and phenols. "In vitro" biological activities include antioxidant, antitumor, antipathogenic, immunomodulative, cardiovascular-system-protective activities and central-nervous-system activities.
Paeoniaceae are dependent on C3 carbon fixation. They contain ellagic acid, myricetin, ethereal oils and flavones, as well as crystals of calcium oxalate. The wax tubules that are formed primarily consist of palmitone (the ketone of palmitic acid).
Genome.
The basic chromosome number is five. About half of the species of the section "Paeonia" however is tetraploid (4n=20), particularly many of those in the Mediterranean region. Both allotetraploids and autotetraploids are known, and some diploid species are also of hybrid origin.
Taxonomy.
The family name "Paeoniaceae" was first used by Friedrich K.L. Rudolphi in 1830, following a suggestion by Friedrich Gottlieb Bartling that same year. The family had been given other names a few years earlier. The composition of the family has varied, but it has always consisted of "Paeonia" and one or more genera that are now placed in Ranunculales. It has been widely believed that "Paeonia" is closest to "Glaucidium", and this idea has been followed in some recent works. Molecular phylogenetic studies, however, have demonstrated conclusively that "Glaucidium" belongs in the family Ranunculaceae, order Ranunculales, but that "Paeonia" belongs in the unrelated order Saxifragales. The genus "Paeonia" consists of about 35 species, assigned to three sections: "Moutan", "Onaepia" and "Paeoniae". The section "Onaepia" only includes "P. brownii" and "P. californicum". The section "Moutan" is divided into "P. delavayi" and "P. ludlowii", together making up the subsection "Delavayanae", and "P. catayana", "P. decomposita", "P. jishanensis", "P. osti", "P. qiui" and "P. rockii" which constitute the subsection "Vaginatae". "P. suffruticosa" is a cultivated hybrid swarm, not a naturally occurring species.
The remainder of the species belongs to the section "Paeonia", which is characterised by a complicated reticulate evolution. Only about half of the (sub)species is diploid, the other half tetraploid, while some species both have diploid and tetraploid populations. In addition to the tetraploids, are some diploid species also likely the result of hybridisation, or nothospecies. Known diploid taxa in the "Paeonia"-section are "P. anomala", "P. lactiflora", "P. veitchii", "P. tenuifolia", "P. emodi", "P. broteri", "P. cambedessedesii", "P. clusii", "P. rhodia", "P. daurica" subsps. "coriifolia", "daurica", "macrophylla" and "mlokosewitschii". Tetraploid taxa are "P. arietina", "P. officinalis", "P. parnassica", "P. banatica", "P. russi", "P. peregrina", "P. coriacea", "P. mascula" subsps. "hellenica" and "mascula", and "P. daurica" subsps. "tomentosa" and "wittmanniana". Species that have both diploid and tetraploid populations include "P. clusii", "P. mairei" and "P. obovata". "P. anomala" was proven to be a hybrid of "P. lactiflora" and "P. veitchii", although being a diploid with 10 chromosomes. "P. emodi" and "P. sterniana" are diploid hybrids of "P. lactiflora" and "P. veitchii" too, and radically different in appearance. "P. russi" is the tetraploid hybrid of diploid "P. lactiflora" and "P. mairei", while "P. cambedessedesii" is the diploid hybrid of "P. lactiflora", likely "P. mairei", but possibly also "P. obovata". "P. peregrina" is the tetraploid hybrid of "P. anomala" and either "P. arietina", "P. humilis", "P. officinalis", "P. parnassica" or less likely "P. tenuifolia", or one of their (now extinct) common ancestors. "P. banatica" is the tetraploid hybrid of "P. mairei" and one of this same group. "P. broteri", "P. coriacea", "P. clusii", "P. rhodia", "P. daurica" subsp. "mlokosewitschi", "P. mascula" subsp. "hellenica" and ssp. "mascula", and "P. daurica" subsp. "wittmanniana" are all descendants of hybrids of "P. lactiflora" and "P. obovata".
Phylogeny.
Recent genetic analyses relate the monogeneric family Paeoniaceae to a group of families with woody species in the order Saxifragales. This results in the following relationship tree. One dissertation suggests the section "Onaepia" branches off earliest, but a later publication of the same author and others suggests the "Moutan"-section splits off first. Within that section "P. ludlowii" and "P. delavayi" are more related to each other than to any other species.
Etymology.
The peony is named after Paeon (also spelled Paean), a student of Asclepius, the Greek god of medicine and healing. In Greek mythology, when Asclepius became jealous of his pupil, Zeus saved Paeon from the wrath of Asclepius by turning him into the peony flower.
Distribution.
The genus "Paeonia" naturally occurs in the temperate and cold areas of the Northern Hemisphere. The section "Moutan", which includes all woody species, is restricted in the wild to Central and Southern China, including Tibet. The section "Onaepia" consist of two herbaceous species and is present in the West of North-America, "P. brownii" between southern British Columbia and the Sierra Nevada in California and eastward to Wyoming and Utah, while "P. californica" is limited to the coastal mountains of Southern and Central California.
The section "Paeonia", which comprises all other herbaceous species, occurs in a band stretching roughly from Morocco and Spain to Japan.
One species of the section "Paeonia", "P. anomala", has by far the largest distribution, which is also north of the distribution of the other species: from the Kola peninsula in North-West Russia, to Lake Baikal in Siberia and South to the Tien Shan Mountains of Kazakhstan. The rest of the section concentrates around the Mediterranean, and in Asia.
The species around the Mediterranean include "Paeonia algeriensis" that is an endemic of the coastal mountains of Algeria, "P. coriacea" in the Rif Mountains and Andalusia, "P. cambessedesii" on Majorca, "P. russoi" on Corsica, Sardinia and Sicilly, "P. corsica" on Corsica, Sardinia, the Ionian islands and in western Greece", P. clusii" subsp. "clusii" on Crete and Karpathos, and subsp. "rhodia" on Rhodes, "P. kesrouanensis" in the Western Taurus Mountains, "P. arietina" from the Middle Taurus Mountains, "P. broteri" in Andalucia, "P. humilis" from Andalucia to the Provence, "P. officinalis" from the South of France, through Switzerland to the Middle of Italy, "P. banatica" in western Romania, northern Serbia and Slovenia and in southern Hungary, "P. peregrina" in Albania, western Bulgaria, northern Greece, western Romania, Serbia, Montenegro and Bosnia, while "P. mascula" has a large distribution from Catalonia and southern France to Israel and Turkey.
Between the two concentrations, the subspecies of "Paeonia daurica" occur, with subspecies "velebitensis" in Croatia, and "daurica" in the Balkans and Crimea, while the other subspecies "coriifolia", "macrophylla", "mlokosewitschii", "tomentosa" and "wittmanniana" are known from the Caucasus, Kaçkar and Alborz Mountains.
"Paeonia emodi" occurs in the western Himalayas between Pakistan and western Nepal, "P. sterniana" is an endemic of southeastern Tibet, "P. veitchii" grows in Central China (Qinghai, Ningxia, Gansu, Shaanxi, Shanxi, Sichuan and the eastern rim of Tibet), like "P. mairei" (Gansu, Guizhou, Hubei, Shaanxi, Sichuan, and Yunnan), while "P. obovata" grows in warm-temperate to cold China, including Manchuria, Korea, Japan, Far Eastern Russia (Primorsky Krai) and on Sakhalin, and "P. lactiflora" occurs in Northern China, including Manchuria, Japan, Korea, Mongolia, Russia (Far East and Siberia).
Distributional history.
The species of the section Paeonia have a disjunct distribution, with most of the species occurring in the Mediterranean, while many others occur in eastern Asia. Genetic analysis has shown that all Mediterranean species are either diploid or tetraploid hybrids that resulted from the crossbreeding of species currently limited to eastern Asia. The large distance between the ranges of the parent species and the nothospecies suggest that hybridisation already occurred relatively long ago. It is likely that the parent species occurred in the same region when the hybrids arose, and were later exterminated by successive Pleistocene glaciations, while the nothospecies remained in refugia to the South of Europe. During their retreat "P. lactiflora" and "P. mairei" likely became sympatric and so produced the Himalayan nothospecies "P. emodi" and "P. sterniana".
Cultivation.
Ancient Chinese texts mention the peony was used for flavoring food. Confucius (551–479 BC) is quoted to have said: "I eat nothing without its sauce. I enjoy it very much, because of its flavor." Peonies have been used and cultivated in China since early history. Ornamental cultivars were created from plants cultivated for medicine in China as of the sixth and seventh century. Peonies became particularly popular during the Tang dynasty, when they were grown in the imperial gardens. In the tenth century the cultivation of peonies spread through China, and the seat of the Sung dynasty, Luoyang, was the centre for its cultivation, a position it still holds today. A second centre for peony cultivation developed during the Qing dynasty in Cáozhōu, now known as He Ze. Both cities still host annual peony exhibitions and state-funded peony research facilities. Before the tenth century, "P. lactiflora" was introduced in Japan, and over time many varieties were developed both by self fertilisation and crossbreeding, particularly during the eighteenth to twentieth centuries (middle Edo to early Shōwa periods). During the 1940s Toichi Itoh succeeded in crossing tree peonies and herbaceous peonies and so created a new class of so-called intersectional hybrids. Although "P. officinalis" and its cultivars were grown in Europe from the fifteenth century on, originally also for medicinal purposes, intensive breeding started only in the nineteenth century when "P. lactiflora" was introduced from its native China to Europe. The tree peony was introduced in Europe and planted in Kew Gardens in 1789. The main centre of peony breeding in Europe has been in the United Kingdom, and particularly France. Here, breeders like Victor Lemoine and François Félix Crousse selected many new varieties, mainly with "P. lactiflora", such as "Avant Garde" and "Le Printemps". The Netherlands is the largest peony cut flower producing country with about 50 million stems each year, with "Sarah Bernhardt" dominating the sales with over 20 million stems. An emerging source of peonies in mid to late summer is the Alaskan market. Unique growing conditions due to long hours of sunlight create availability from Alaska when other sources have completed harvest.
Plant growth habits.
Peony species come in two distinct growth habits, while hybrid cultivars in addition may occupy an intermediate habit.
Flower types.
Six types of flower are generally distinguished in cultivars of herbaceous peonies.
Propagation.
Herbaceous and Itoh peonies are propagated by root division, and sometimes by seed. Tree peonies can be propagated by grafting, division, seed, and from cuttings, although root grafting is most common commercially.
Herbaceous peonies such as "Paeonia lactiflora", will die back to ground level each autumn. Their stems will reappear the following spring. However tree peonies, such as "Paeonia suffruticosa", are shrubbier. They produce permanent woody stems that will lose their leaves in winter but the stem itself remains intact above ground level.
Hybrid cultivars.
The following hybrids and cultivars have gained the Royal Horticultural Society's Award of Garden Merit:-
Uses.
The herb known as Paeonia, in particular the root of "P. lactiflora" (Bai Shao, Radix Paeoniae Lactiflorae), has been used frequently in traditional medicines of Korea, China and Japan. In Japan, "Paeonia lactiflora" used to be called "ebisugusuri" ("foreign medicine"). Pronunciation of 牡丹 (peony) in Japan is "botan." In "kampo" (the Japanese adaptation of Chinese medicine), its root was used as a treatment for convulsions. It is also cultivated as a garden plant. In Japan "Paeonia suffruticosa" is called the "King of Flowers" and "Paeonia lactiflora" is called the "Prime Minister of Flowers."
In China, the fallen petals of "Paeonia lactiflora" are parboiled and sweetened as a tea-time delicacy. Peony water, an infusion of peony petals, was used for drinking in the Middle Ages. The petals may be added to salads or to punches and lemonades.
Peonies are also extensively grown as ornamental plants for their very large, often scented flowers.
Culture.
The peony is among the longest-used flowers in Eastern culture. Along with the plum blossom, it is a traditional floral symbol of China, where the "Paeonia suffruticosa" is called 牡丹 (mǔdān). It is also known as 富貴花 (fùguìhuā) "flower of riches and honour" or 花王 (huawang) "king of the flowers", and is used symbolically in Chinese art. In 1903, the Qing dynasty declared the peony as the national flower. Currently, the Republic of China government in Taiwan designates the plum blossom as the national flower, while the People's Republic of China government has no legally designated national flower. In 1994, the peony was proposed as the national flower after a nationwide poll, but the National People's Congress failed to ratify the selection. In 2003, another selection process was initiated, but no choice has been made to date.
The ancient Chinese city Luoyang has a reputation as a cultivation centre for the peonies. Throughout Chinese history, peonies in Luoyang have been said to be the finest in the country. Dozens of peony exhibitions and shows are still held there annually.
In the Middle Ages, peonies were often painted with their ripe seed-capsules, since it was the seeds, not the flowers, which were medically significant. Ancient superstition dictated that great care be taken not to be seen by a woodpecker while picking the plant's fruit, or the bird might peck out one's eyes.
The red flowers of the species "Paeonia peregrina" are important in Serbian folklore. Known as Kosovo peonies (, ), they are said to represent the blood of Serbian warriors who died in the Battle of Kosovo.
In 1957, the Indiana General Assembly passed a law to make the peony the state flower of Indiana, a title which it holds to this day. It replaced the zinnia, which had been the state flower since 1931.
Mischievous nymphs were said to hide in the petals of the Peony, giving it the meaning of Shame or Bashfulness in the Language of Flowers. While the peony takes several years to re-establish itself when moved, it blooms annually for decades once it has done so.
Peonies tend to attract ants to the flower buds. This is due to the nectar that forms on the outside of the flower buds, and is not required for the plants' own pollination or other growth. The presence of ants is thought to provide some deterrence to other harmful insects though, so the production of ant-attracting nectar is plausibly a functional adaptation. Ants do not harm the plants.
Peonies are a common subject in tattoos, often used along with koi-fish. The popular use of peonies in Japanese tattoo was inspired by the ukiyo-e artist Utagawa Kuniyoshi's illustrations of "Suikoden", a classical Chinese novel. His paintings of warrior-heroes covered in pictorial tattoos included lions, tigers, dragons, koi fish, and peonies, among other symbols. The peony became a masculine motif, associated with a devil-may-care attitude and disregard for consequence.
Famous painters of peonies have included Conrad Gessner (ca. 1550) and Auguste Renoir in 1879. "Paeonia officinalis" can be found in the altar picture of "Maria im Rosenhag" by Schongauer in the former Dominican Church in Colmar. The Italian Jesuit, painter and architect Giuseppe Castiglione (1688-1766), who worked at the court of the Qianlong Emperor in the Qing dynasty, painted peonies.