Rheum (plant)

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Rheum
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Polygonaceae
Subfamily: Polygonoideae
Genus: Rheum
L.
Species

See text.

Synonyms[1]
  • Rhabarbarum Fabr.

Rheum

perennial plants in the family Polygonaceae. Species are native to eastern Europe, southern and eastern temperate Asia, with a few reaching into northern tropical Asia. Rheum is cultivated in Europe and North America.[1] The genus includes the vegetable[3] rhubarb. The species have large somewhat triangular shaped leaves with long, fleshy petioles. The flowers are small, greenish-white to rose-red, and grouped in large compound leafy inflorescences. A number of cultivars
of rhubarb have been domesticated both as medicinal plants and for human consumption. While the leaves are slightly toxic, the stalks are used in pies and other foods for their tart flavor.

Description

Rheum ribes growing in Iran

Rheum species are herbaceous perennials growing from fleshy roots. They have upright growing stems and mostly basal, deciduous leaves growing from short, thick

ovary is simple and triangular shaped with three erect or deflexed styles. The stigmas are head-like. The fruits are a three-sided achene with winged sides, and the seeds are albuminous with a straight or curved embryo
.

Seeds

Taxonomy

The genus Rheum was erected in 1753 by

Volga River § Nomenclature
.)

In 1936

USSR, and furthermore two introduced species, one variety, and one form.[11] The 1989 Plants of Central Asia, dealing with a larger geographical remit, has Alisa E. Grabovskaya-Borodina recognising only 12 species, synonymising a great number.[12] The Vascular plants of Russia and adjacent states of 1995 accepted 17 species for the states of the former USSR, re-recognising many of the taxa as species.[13] In the Flora of China in 2003 Borodina and Bao Bojian recognise 38 species (of which 19 are endemic) in China, including a number Borodina considered synonyms in 1989.[14]

Intergeneric relationships

Rheum is placed in the family Polygonaceae, subfamily Polygonoideae. Within the subfamily, it is in the tribe Rumiceae, along with the two genera Oxyria and Rumex. It is most closely related to Rumex.[15]

Rumiceae

Oxyria

Rumex

Rheum

Infrageneric classification

In the 1998 Flora Republicae popularis Sinicae A. R. Li proposed classifying the Chinese representatives of the genus into five sections. These sections are distinct morphologically, but as of 2010 studies in karyotypy, pollen morphology or molecular data (chloroplast DNA) have failed to elucidate interspecific relationships.[16][17]

  • Sect. Rheum - Generally mid-sized species with entire, un-lobed leaves and whitish flowers.
  • Sect. Deserticola (Maxim.) Losinsk. - Smallish species native to harsh desert environments.
  • Sect. Nobilia A.R. Li - Large, monocarpic, high altitude species from the Himalayas that create their own mini-greenhouse by having an inflorescence tightly protected by transparent bracts.
  • Sect. Palmata Losinsk. - The largest rhubarbs to 2m tall, with
    palmate
    , or otherwise lobed, leaves and reddish flowers.
  • Sect. Spiciforma A.R. Li - Generally stemless, high altitude species with curiously hard, leathery leaves and an inflorescence with thin, spike-like panicles. Including many dwarf species.
Rheum nanum is the sole species in Losinskaja's section Acaulia

Losinskaja used a slightly different classification in the Flora SSSR in 1936:[11]

  • Sect. Acaulia Losinsk.
  • Sect. Deserticola (Maxim.) Losinsk.
  • Sect. Glabrifolia Losinsk.
  • Sect. Palmata Losinsk.
  • Sect. Rhapontica Losinsk.
  • Sect. Ribesiformia Losinsk.
  • Sect. Spiciformia Losinsk.

Species

Rheum tibeticum in May, cultivated in Poland.
Rheum nobile

The genus is represented by about 50–60 extant species.[1][17] The many cultivars of culinary rhubarb more usually grown for eating are recognised as Rheum × hybridum in the Royal Horticultural Society's list of recognised plant names. The drug rheum is prepared from the rhizomes and roots of another species, R. officinale or medicinal rhubarb. This species is also native to Asia, as is the turkey rhubarb, R. palmatum. Another species, the Sikkim rhubarb, R. nobile, is limited to the Himalayas.

The

centre of diversity for this genus is found in Central Asia.[18]

The following is a partial list of species names, some of which, according to some authorities, are considered synonyms or not fully resolved or accepted:[13][14][19]

Ecology

Rheum species have been recorded as

Arctia caja, Hydraecia micacea and Xestia baja.[20]

Rheum species are often the

host plants for myrmecophilous caterpillars of the butterfly genus Callophrys; Callophrys titanus feeds on R. maximowiczii in southern Kazakhstan,[21] C. mystaphia on R. ribes in eastern Turkey,[22] and C. mystaphioides on R. persicum in southwest and central Iran.[23] The caterpillars of the related Lycaena violacea from southeastern Siberia are only known to feed on R. rhabarbarum.[20]

R. ribes leaves are food for the moth

jewel beetle Capnodis marquardti, and the leaf beetle Labidostomis brevipennis.[25]

In the Taldy-Bulak valley in the Talas Alatau of Kyrgyzstan, the emerging leaves of R. maximowiczii are an important food source for Himalayan brown bear (Ursus arctos ssp. isabellinus) awakening from hibernation in April.[26]

Uses

Many Rheum species have food and medicinal uses. Some of these uses originated in Asia more than 2,000 years ago. All parts of the plant contain slightly

anthraquinone glycosides, and the raw or cooked leaf blades are poisonous to humans and livestock if consumed in large enough amounts.[27]
Plants in cultivation are propagated by cutting up the crowns of larger plants and by seeds.

Rheum tanguticum (syn. R. palmatum var. tanguticum)

Some species are grown for their ornamental qualities, including R. acuminatum, R. alexandrae, R. australe, R. kialense, R. palmatum, R. rhabarbarum and R. ribes.[28]

The roots of R. macrocarpum are exploited in the

Tian-Shan to make a dye.[11]

References

Wikimedia Commons has media related to Rheum.
  1. ^ a b c "Rheum L." Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2019-03-10.
  2. ^ From Ancient Greek ῥῆον.
  3. ^ Vegetable Crops Production Guide for the Atlantic Provinces[dead link]
  4. ^ "Plant Name Details for Rheum L." The International Plant Names Index. Retrieved 2019-03-12.
  5. ^ Linnaeus, Carolus (1753). "Rheum ribes". Species Plantarum, Tomus I. Stockholm: Impensis Laurentii Salvii. Retrieved 2019-03-11.
  6. ISBN 978-0-19-866189-4
    .
  7. ^
    ISBN 978-1-4834-1859-9
    .
  8. ^
    ISBN 0-620-23435-0
    .
  9. ^ J.P. Mallory & D.Q. Adams, Encyclopedia of Indo-European Culture, s.v. "dew" (London: Fitzroy Dearborn, 1997), 158-9.
  10. ISBN 978-0-900513-04-6
    .
  11. ^ a b c Лозина-Лозинская, Агния Сергеевна (1936). "Rheum". In Комаро́в, Влади́мир Лео́нтьевич (ed.). Flora SSSR, Vol. 5 (in Russian). Moscow: Издателство Академии Наук СССР. pp. 482–501.
  12. ^ Бородина, А.Е.; Грубов, В.И.; Грудзинская, И.А.; Меницкий, Ю.Л. (1989). Растения Центральной Азии. По материалам Ботанического института им. В.Л.Комарова. Вып. 9. Ивовые - Гречишные. Л. [Plants of Central Asia: plant collections from China and Mongolia, Vol. 9] (in Russian). Moscow: Издателство Академии Наук СССР. pp. 77–93.
  13. ^
    ISBN 0-521-45006-3
    .
  14. ^ a b Bojian (包伯坚), Bao; Grabovskaya-Borodina, Alisa E. (2003). "Rheum". In Zhengyi (吴征镒), Wu; Raven, Peter H.; Deyuan (洪德元), Hong (eds.). Flora of China, Vol. 5. Beijing: Science Press. p. 341.
  15. doi:10.12705/646.5
    .
  16. S2CID 86616077
    . Retrieved 24 March 2019.
  17. ^
    PMID 15994840
    .
  18. ^ Грубов, В.И. (1963). Растения Центральной Азии. По материалам Ботанического института им. В.Л.Комарова. Вып. 1. Введение, Папоротники, Библиография. Л. [Plants of Central Asia: plant collections from China and Mongolia, Vol. 1] (in Russian). Moscow: Издателство Академии Наук СССР. p. 20.
  19. ^ "The Plant List: Rheum". Royal Botanic Garden, Kew and Missouri Botanic Garden. Retrieved 3 April 2019.
  20. ^ a b Savela, Markku. "Rheum". Lepidoptera and some other life forms. Markku Savela. Retrieved 16 March 2019.
  21. ^ Savela, Markku. "Callophrys". Lepidoptera and some other life forms. Markku Savela. Retrieved 5 April 2019.
  22. ^ Van Gölü Havzasında Kelebek Çeşitliliği (Diversity of the butterflies in Van Lake Basin East Turkey) by Muhabbet Kemal, 2008
  23. doi:10.11646/zootaxa.3619.4.4
    . Retrieved 5 April 2019.
  24. ^ Muhabbet Kemal, Halil Özkol & Lokman Kayci (2008), Xylena Ochsenheimer in East Turkey with new provincial records and larval food-plants (Noctuidae, Lepidoptera), in Miscellaneous Papers, Centre for Entomological Studies Ankara, no: 139-140, 20.03.2008
  25. doi:10.12976/jib/2016.4.1
    . Retrieved 16 March 2019.
  26. ^ Vladimir Kolbintsev & Kurt Vickery (April 2013). The Tulips of the Tien Shan (PDF) (Report). Greentours Natural History Holidays. Retrieved 2 April 2019.
  27. ^ Rheum rhabarbarum in Flora of North America @. Efloras.org. Retrieved on 2015-05-02.
  28. ISBN 0-88192-159-9
    .
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