Peony
The peony or paeony is any 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 describes 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 lasting for 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 they generally are 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, 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 free stamens, with anthers fixed at their base to the filaments, and are sagittate in shape, open with longitudinal 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 of separate carpels, which have a very short style and a decurrent stigma. Each of these develops into a dry fruit, 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.
Genome
The basic chromosome number is five. About half of the species of the section Paeonia however is tetraploid, 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. californica. The section Moutan is divided into P. delavayi and P. ludlowii, together making up the subsection Delavayanae, and P. cathayana, 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 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 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.Species
- Herbaceous species
- *Paeonia algeriensis
- *Paeonia anomala
- *Paeonia turcica
- *Paeonia arietina
- *Paeonia broteri
- *Paeonia brownii
- *Paeonia californica
- *Paeonia cambessedesii
- *Paeonia clusii
- **subsp. clusii
- **subsp. rhodia
- *Paeonia coriacea
- *Paeonia corsica
- *Paeonia daurica
- **subsp. coriifolia
- **subsp. daurica
- **subsp. macrophylla
- **subsp. mlokosewitschii
- **subsp. tomentosa
- **subsp. velebitensis
- **subsp. wittmanniana
- *Paeonia emodi
- *Paeonia intermedia
- *Paeonia kesrouanensis
- *Paeonia lactiflora
- *Paeonia mairei
- *Paeonia mascula
- **subsp. mascula
- **subsp. bodurii
- **subsp. hellenica
- **subsp. russoi
- *Paeonia obovata
- **subsp. willmottiae
- *Paeonia officinalis
- *Paeonia parnassica
- *Paeonia peregrina
- *Paeonia sterniana
- *Paeonia tenuifolia
- *Paeonia veitchii
- Woody species, tree peonies
- *Paeonia decomposita
- *Paeonia delavayi
- *Paeonia jishanensis
- *Paeonia ludlowii
- *Paeonia ostii
- *Paeonia qiui
- *''Paeonia rockii''
Distribution
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 Sicily, 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, like P. mairei, while P. obovata grows in warm-temperate to cold China, including Manchuria, Korea, Japan, Far Eastern Russia and on Sakhalin, and P. lactiflora occurs in Northern China, including Manchuria, Japan, Korea, Mongolia, Russia.