''Rheum palmatum'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the knotweed

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Polygonaceae. It is commonly called Chinese rhubarb, ornamental rhubarb, Turkey rhubarb or East Indian rhubarb. ''Rheum palmatum'' is a

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of ...

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

related to the edible

rhubarb Rhubarb is the fleshy, edible stalks ( petioles) of species and hybrids (culinary rhubarb) of ''Rheum'' in the family Polygonaceae, which are cooked and used for food. The plant is a herbaceous perennial that grows from short, thick rhizomes. ...

. It is primarily used in traditional medicine, and as an ornamental subject in the garden.

Taxonomy

Agnia Losina-Losinskaja Agnia Sergeyevna Losina-Losinskaja () (1903–1958) was a Soviet botanist. Her family name is also transcribed as Lozina-Lozinscaia, and Lozina-Lozinskaja. She is the author or co-author of the botanical names of at least 216 taxa, including spe ...

proposed classifying it in the

section Section, Sectioning, or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sig ...

''Palmata'' in the ''Flora SSSR'' in 1936. In the 1998 ''Flora Republicae popularis Sinicae'' A. R. Li maintains this classification for this species.

Description

Its lobed leaves are large, jagged and hand-shaped, growing in width to two feet, but sometimes up to a full meter (3ft 3in) in width and length). The tiny pink flowers are in

panicles In botany, a panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a p ...

up to five feet (1.5 meters) in height. Chinese rhubarb has thick, deep roots.

Similar species

The species ''

Rheum tanguticum Rheum (; from Greek language, Greek: wikt:ῥεῦμα, ῥεῦμα ''rheuma'' 'a flowing, rheum') is a thin mucus naturally discharged from the eyes, nose, or mouth, often during sleep (contrast with mucopurulent discharge).Amodio, Aime"Where ...

'' is closely related to ''R. palmatum''. ''R. palmatum'' can be distinguished from ''R.'' × ''hybridum'', the garden rhubarb we eat, by size; while garden rhubarb only grows to a few feet in height, Chinese rhubarb can grow to six feet.

Karyotypy

''R. palmatum'' has a

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

count of 2''n''=22.

Distribution

It is native in the regions of

western China Western China ( zh, s=中国西部, l=, labels=no or zh, s=华西, l=, labels=no) is the west of China. It consists of Southwestern China and Northwestern China. In the definition of the Chinese government, Western China covers six provinces ...

, northern

Tibet Tibet (; ''Böd''; ), or Greater Tibet, is a region in the western part of East Asia, covering much of the Tibetan Plateau and spanning about . It is the homeland of the Tibetan people. Also resident on the plateau are other ethnic groups s ...

, and the Mongolian Plateau.

Folk medicine

'', ''Rheum palmatum'', '' R. rhabarbarum'' and '' R. officinale'' and a few others, are all harvested for their roots, which are used as a herbal medicine. ''Rheum palmatum'' (or ''dahuang'') is an important crop that has been used in traditional Chinese medicine for over 2,000 years. The dried roots of Chinese rhubarb became one of the most prominent items traded along the

Silk Road The Silk Road was a network of Asian trade routes active from the second century BCE until the mid-15th century. Spanning over , it played a central role in facilitating economic, cultural, political, and religious interactions between the ...

. Imported roots of various rhubarb species were widely used in Europe for hundreds of years before the identity of the plant was eventually discovered. Some of the common names associated with ''Rheum palmatum''"Russian rhubarb", "Turkey rhubarb", and "Indian rhubarb"are directly affiliated with the trade routes for rhubarb from China. The root is known for its purported purging effects and suppressing fever. In ancient China, rhubarb root was taken to try to cure stomach ailments and as a "cathartic" (an agent used to relieve constipation), and used as a

poultice A poultice or cataplasm, also called a fomentation, is a soft moist mass, often heated and medicated, that is applied to the skin to reduce inflammation, soothe pain, promote healing, or otherwise treat wounds or ailments. Soft materials like cer ...

for "fevers and edema" (swelling caused by fluid retention in the body tissues). It was given its Latin name by

Carolus Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the year 1759 and first grown in Britain around 1762. The first International Symposium on Rhubarb was held in China in 1990. Its objective was to verify the scientific data and treatment of Chinese Rhubarb used by Chinese

pharmacopoeia A pharmacopoeia, pharmacopeia, or pharmacopoea (or the typographically obsolete rendering, ''pharmacopœia''), meaning "drug-making", in its modern technical sense, is a reference work containing directions for the identification of compound med ...

Health risks

Pregnant women should avoid all intake of the plant since it may cause uterine stimulation. If taken for an extended amount of time, adverse effects include: "hypertrophy of the liver, thyroid, and stomach, as well as nausea, griping, abdominal pain, vomiting, and diarrhea." Though the root of the Chinese rhubarb is a key facet of herbal medicine, its leaves can actually be poisonous if consumed in large amounts due to the

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and chemical formula , also written as or or . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name i ...

content. Patients with "arthritis, kidney problems, inflammatory bowel disease, or intestinal obstruction" should refrain from consumption.

Cultivation

Ornamental use

With its large palmate leaves and tall panicles of pink flowers, ''Rheum palmatum'' is a bold statement plant for the temperate garden, that grows up to tall and broad. It is hardy down to . It is propagated by seed in the spring, or by root division in spring or autumn. It grows best in full sunlight in well-drained soil. The following cultivars have gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

:- * 'Ace of Hearts' – compact cultivar to * 'Bowles's Crimson' * 'Hadspen Crimson'

Farming as medicinal herb

Since it is the roots and

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

which serve as this plant's source of medicinal usage, special care is taken in their preparation. When 6–10 years old, the rhizomes of these plants are removed from the ground in the autumn when both its stems and leaves changed to yellow wild. Furthermore, the lateral rootlets and the crown are removed, leaving only the root. Any debris around the root is cleaned off, the coarse exterior bark removed, and the root cut and divided into cube-like pieces to increase its surface area, thereby decreasing the time needed for drying.

References

{{Authority control palmatum Plants described in 1759 Taxa named by Carl Linnaeus