Rheum palmatum is a species of flowering plant in the knotweed family Polygonaceae. It is commonly called Chinese rhubarb,[1][2]ornamental rhubarb,[3]Turkey rhubarb[2] or East Indian rhubarb.[2]
Rheum palmatum is a herbaceousperennial related to the edible rhubarb. It is primarily used in traditional medicine, and as an ornamental subject in the garden.
Taxonomy
Agnia Losina-Losinskaja proposed classifying it in the sectionPalmata in the Flora SSSR in 1936.[4] In the 1998 Flora Republicae popularis Sinicae A. R. Li maintains this classification for this species.[5]
Description
Loosely branched clusters of matured red flowers found on the lobed-leafed Chinese rhubarb.Habit of Rheum palmatum
It is a perennial herbaceous plant growing to 1.5–2m (4ft 11in– 6ft 7in) tall.[6] Its lobed leaves are large, jagged and hand-shaped, growing to 40–60cm (16–24in) wide and long, occasionally to 100cm (39in). The tiny pink flowers are in panicles up to 1.5m (4ft 11in) tall.[7] Chinese rhubarb has thick, deep roots.[8]
R. palmatum can be distinguished from the garden rhubarb R. × hybridum, by size; while garden rhubarb only grows to around a metre in height, Chinese rhubarb can grow to two metres.[6]
Rheum tanguticum, Rheum palmatum, R. rhabarbarum and R. officinale and a few others, are all harvested for their roots, which are used as a herbal medicine.[9]Rheum palmatum (or dahuang) is an important crop that has been used in traditional Chinese medicine for over 2,000 years.[10]
The dried roots of Chinese rhubarb became one of the most prominent items traded along the Silk Road.[8] Imported roots of various rhubarb species were widely used in Europe for hundreds of years before the identity of the plant was eventually discovered.[8] 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.[8]
The root is known for its purported purging effects and suppressing fever.[8] 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 for "fevers and edema" (swelling caused by fluid retention in the body tissues).[8] It was given its Latin name by Carolus Linnaeus in the year 1759 and first grown in Britain around 1762.[8]
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 pharmacopoeias.[8]
Health risks
Pregnant women should avoid all intake of the plant since it may cause uterine stimulation.[8] 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."[8]
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 content.[8] Patients with "arthritis, kidney problems, inflammatory bowel disease, or intestinal obstruction" should refrain from consumption.[8]
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 2.5m (8.2ft) tall and broad. It is hardy down to −20°C (−4°F).[11] It is propagated by seed in the spring, or by root division in spring or autumn.[9] It grows best in full sunlight in well-drained soil.[9]
Since it is the roots and rhizome which serve as this plant's source of medicinal usage, special care is taken in their preparation.[8] 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.[9] Furthermore, the lateral rootlets and the crown are removed, leaving only the root.[9] 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.[8]
1 2 3 Eisenreich, Dan (1996–2010). "Rhubarb Botanical Information". The Rhubarb Compendium. Archived from the original on July 10, 2010. Retrieved 2011-02-07.
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