Difference between revisions of "Rhubarb" - New World Encyclopedia

From New World Encyclopedia
Line 39: Line 39:
 
The drug rheum is prepared from the rhizomes and [[root]]s of another species, ''[[Rheum officinale|R. officinale]]'', known as "medicinal rhubarb" or "Chinese rhubarb" (ITIS 1999c). This species is also native to Asia, as is the [Turkey rhubarb]] (''R. palmatum''), which sometimes also is called Chinese rhubarb (ITIS 1999e). Another species, the [[Sikkim rhubarb]] (''R. nobile''), is limited to the [[Himalayas]].
 
The drug rheum is prepared from the rhizomes and [[root]]s of another species, ''[[Rheum officinale|R. officinale]]'', known as "medicinal rhubarb" or "Chinese rhubarb" (ITIS 1999c). This species is also native to Asia, as is the [Turkey rhubarb]] (''R. palmatum''), which sometimes also is called Chinese rhubarb (ITIS 1999e). Another species, the [[Sikkim rhubarb]] (''R. nobile''), is limited to the [[Himalayas]].
  
''Rheum'' species have been recorded as [[larva]]l food plants for some [[Lepidoptera]] species including [[Brown-tail]], [[Buff Ermine]], [[Cabbage Moth]], [[Large Yellow Underwing]], [[Nutmeg (moth)|The Nutmeg]], [[Setaceous Hebrew Character]] and [[Turnip Moth]].
+
''Rheum'' species have been recorded as [[larva]]l food plants for some [[Lepidoptera]] species including [[brown-tail]], [[buff ermine]], [[cabbage moth]], [[large yellow underwing]], [[nutmeg (moth)|the nutmeg]], [[setaceous Hebrew character]], and [[turnip moth]].
 
 
 
 
 
 
  
 
==Cultivation and consumption==
 
==Cultivation and consumption==

Revision as of 02:38, 10 June 2008

Rhubarb
Rheum rhabarbarum.2006-04-27.uellue.jpg
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Caryophyllales
Family: Polygonaceae
Genus: Rheum
L.
Species

About 60, including:

  • Rheum nobile
  • Rheum officinale
  • Rheum palmatum
  • Rheum rhabarbarum
  • Rheum rhaponticum

Rhubarb is the common name for perennial plants comprising the genus Rheum of the Polygonaceae family, and in particular the garden rhubard, Rheum rhabarbarum, which is popularly cultivated for its long, fleshy, edible leafstalks (petioles), which are sweetened and cooked. Plants of the Rheum genus grow from thick, short rhizomes and are characterized by large leaves that are somewhat triangular shaped, small flowers grouped in large, compound, leafy inflorenscenes, and long fleshy petioles.

A number of varieties of rhubarb have been domesticated both as medicinal plants and for human consumption. In addition to garden rhubarb, other well-known rhubarbs include false rhubarb (Rheum rhaponticum), used in cooking, and Chinese rhubarb (Rheum officinale), used medicinally (ITIS 1999b, 1999c, 1999d).

While the leaves are toxic, the stalks are used in pies and other foods for their tart flavor.

Overview and description

The Rheum genus belongs to the knotweed or smartweed family, Polygonaceae. The name is based on the genus Polygonum. In addition to rhubarb, some well known members include Fagopyrum (buckwheat), Rumex (sorrel), and Polygonum (knotgrass). The family is named for the many swollen node joints that some species have; poly means many and goni means knee or joint, though some interpret goni to mean seed, and the name then would refer to the many seeds these plants often produce.

Leaves of Polygonoideae are simple, arranged alternately on the stems, and have a peculiar pair of sheathing stipules known as ocreae. Those species that do not have the nodal ocrea can be identified by having involucrate flower heads. The calyx is petaloid, often in two rows. The flowers are normally bisexual, small in size, actinomorphic with calyxs of 3 or 6 imbricate sepels. After flowering, the sepals often become membranous and enlarge around the developing fruit. Flowers lack a corolla and the sepals are petal-like and colorful. The androecium is composed of 3 to 8 stamens that are normally free or united at the base. Flowers have compound pistils composed of three united carpels with one locule—producing a single ovule. The ovary is superior with basal placentation, and 2 to 4 stigmas are produced (Jones and Luchsinger 1979).

Rhubarb growing

Rheum, the rhubarb genus, is a genus of flowering plants that grow from thick short rhizomes. Rheum species are herbaceous perennials with hermaphrodite flowers, consisting of a colored perianth, composed of six to nine segments, arranged in two rows. The flowers typically are small, greenish-white to rose-red and they have nine stamina inserted on the torus at the base of the peranthium. The flowers are free or subconnatent at their base. The ovary is simple and triangular shaped with three styles. The fruits are a three-sided caryopsis with winged sides and the seeds are albuminous and have straight embryos. The plants have large leaves that are somewhat triangular shaped with long fleshy petioles.

Species

The genus Rheum is represented by about 60 extant species (Wang et al. 2005). Among species found in the wild, those most commonly used in cooking are the "garden rhubarb" (R. rhabarbarum) (ITIS 1999b) and R. rhaponticum, which, though a true rhubarb, bears the common name "false rhubarb" (ITIS 1999c). The many varieties of cultivated rhubarb more usually grown for eating are recognized in general as Rheum x hybridum in the Royal Horticultural Societies list of recognized plant names.

The drug rheum is prepared from the rhizomes and roots of another species, R. officinale, known as "medicinal rhubarb" or "Chinese rhubarb" (ITIS 1999c). This species is also native to Asia, as is the [Turkey rhubarb]] (R. palmatum), which sometimes also is called Chinese rhubarb (ITIS 1999e). Another species, the Sikkim rhubarb (R. nobile), is limited to the Himalayas.

Rheum species have been recorded as larval food plants for some Lepidoptera species including brown-tail, buff ermine, cabbage moth, large yellow underwing, the nutmeg, setaceous Hebrew character, and turnip moth.

Cultivation and consumption

Rhubarb displayed for sale at a grocery

The plant is indigenous to Asia, and many suggest that it was often used by the Mongolians; particularly, the Tatars tribes of the Gobi. The plant has grown wild along the banks of the Volga for centuries; it may have been brought there by Eurasian tribes, such as the Scythians, Huns, Magyars or Mongols. The term rhubarb is a combination of Greek rha and barbarum; rha being a term that referred both to the plant and to the Volga River (McGee 2004, p. 366). Varieties of rhubarb have a long history as medicinal plants in traditional Chinese medicine, but the use of rhubarb as food is a relatively recent innovation, first recorded in 17th century England, after affordable sugar became available to common people, and reaching a peak between the two world wars. Rhubarb first came to America in the 1820s, entering the country in Maine and Massachusetts and moving west with the settlers (Waters 2002).

Rhubarb is now grown in many areas and thanks to greenhouse production is available throughout much of the year. Grown primarily for its fleshy petioles, commonly known as rhubarb sticks or stalks rhubarb is a vegetable that plays at being a fruit. In temperate climates rhubarb is one of the first food plants to be ready for harvest, usually in mid to late Spring (April/May in the Northern Hemisphere, October/November in the Southern), and the season for field-grown plants lasts until September. In the Northwest there are typically two harvests: one from late April through May and another from late June and into July. Rhubarb is ready to be consumed as soon as it is harvested, and freshly cut stalks will be firm and glossy.

The color of the Rhubarb stalks can vary from the commonly associated deep red, through speckled pink, to simply green. The color results from the presence of anthocyanins, and varies according to both rhubarb variety and production technique. The color is not related to its suitability for cooking.[1]: The green-stalked rhubarb is more robust and has a higher yield, and the red-colored stalks are more popular with consumers.

The stalks, which are petioles, can be cooked in a variety of ways. Stewed, they yield a tart sauce that can be eaten with sugar and other stewed fruit or used as filling for pies (see rhubarb pie), tarts, and crumbles. This common use led to the slang term for rhubarb, "pie plant". Cooked with strawberries or apples as a sweetener, or with stem or root ginger, rhubarb makes excellent jam. It can also be used to make wine and as an ingredient in baked goods.

In former days, a common and affordable sweet for children in parts of the United Kingdom and Sweden was a tender stick of rhubarb, dipped in sugar. In the UK the first rhubarb of the year is grown by candlelight in dark sheds dotted around the noted "Rhubarb Triangle" of Wakefield, Leeds and Morley (Wakefield), a practice that produces a sweeter, more tender stalk (McGee 2004, p. 367).

A homemade rhubarb pie

In warm climates, rhubarb will grow all year round, but in colder climates the parts of the plant above the ground disappear completely during winter, and begin to grow again from the root in early spring. It can be forced, that is, encouraged to grow early, by raising the local temperature. This is commonly done by placing an upturned bucket over the shoots as they come up.

Rhubarb can successfully be planted in containers, so long as the container is large enough to accommodate a season's growth.

Rhubarb is used as a strong laxative and for its astringent effect on the mucous membranes of the mouth and the nasal cavity.

Toxic effects

Rhubarb flower.

Rhubarb leaves contain poisonous substances. Rhubarb leaves contain oxalic acid, a corrosive and nephrotoxic acid that is present in many plants. The Template:LD50 (median lethal dose) for pure oxalic acid is predicted to be about 375 mg/kg body weight,[citation needed] or about 25 g for a 65 kg (~140 lb) human. While the oxalic acid content of rhubarb leaves can vary, a typical value is about 0.5%,[1] so a rather unlikely five kilograms of the extremely sour leaves would have to be consumed to reach an Template:LD50 dose of oxalic acid. However, the leaves are believed to also contain an additional, unidentified toxin.[2] In the petioles, the amount of oxalic acid is much lower, only about 2-2.5% of the total acidity[3], especially when harvested before mid-June (in the northern hemisphere), but it is still enough to cause slightly rough teeth.[citation needed]

The roots have been used as strong laxative for over 5,000 years.[4] The roots and stems are rich in anthraquinones, such as emodin and rhein. These substances are cathartic and laxative, which explains the sporadic abuse of Rhubarb as a slimming agent. Anthraquinones are yellow or orange and may colour the urine.[citation needed]

Other uses of the word

Shucked and sliced up rhubarb.jpg

It is or was common for a crowd of extras in acting to shout the word "rhubarb" repeatedly and out of step with each other, to cause the effect of general hubbub. As a result, the word "rhubarb" sometimes is used to mean "length of superfluous text in speaking or writing", or a general term to refer to irrelevant chatter by chorus or extra actors. The American equivalent is walla.

Possibly from this usage, possibly from a variant on "rube", or perhaps some of both, the word also denotes a loud argument. The term has been most commonly used in baseball.

The term "rhubarb" as it relates to baseball is an antiquated reference to a fight amongst many players. The iconic bench-clearing brawl is known as a "rhubarb".

In the 1989 film Batman, The Joker (Jack Nicholson) tells Bruce Wayne (Michael Keaton) to "never rub another man's rhubarb". The term was used as a threat to Bruce Wayne warning him to leave both men's love interest Vicki Vale (Kim Basinger) alone.

In the 1951 film adaptation of the Pulitzer Prize winning play by Tennessee Williams, A Streetcar Named Desire, Stanley (Marlon Brando) gets into a ruckus at the bowling alley. His wife Stella (Kim Hunter) points him out to her sister Blanch (Vivien Leigh) and says, "[he's] the one that's making all the rhubarb", to describe him as the person at the center of, or instigator of, the disruption.

The phrase "out in the rhubarb patch" can be used to describe a place being in the far reaches of an area. Rhubarb is usually grown at the outer edges of the garden in the less desirable and unkept area.[citation needed] Wheras the leaves and roots are poisonous, the stem is not. The term also refers to a 1954 book by Red Barber and Barney Stein, The Rhubarb Patch: The Story of the Modern Brooklyn Dodgers in which "Rhubarb Patch" was used in both it's baseball and more general connotations to describe Ebbets Field, the home of the Brooklyn Dodgers.

In Canada, the phrase "putting it in the rhubarb" describes driving a vehicle off the road, possibly into roadside vegetation.

"Donkey Rhubarb" refers to Japanese knotweed[5] and is also the name of an EP by Aphex Twin

References
ISBN links support NWE through referral fees

  • Integrated Taxonomic Information System (ITIS). 1999a. Rheum L.. ITIS Taxonomic Serial No.: 21318. Retrieved June 9, 2008.
  • —. 1999e. Rheum palmatum L.. ITIS Taxonomic Serial No.: 506564. Retrieved June 9, 2008.

[6]

[7]

[8]

[9]

External links

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.

  1. GW Pucher, AJ Wakeman, HB Vickery. THE ORGANIC ACIDS OF RHUBARB (RHEUM HYBRIDUM). III. THE BEHAVIOR OF THE ORGANIC ACIDS DURING CULTURE OF EXCISED LEAVES. Journal of Biological Chemistry, 1938
  2. Rhubarb leaves poisoning. Medline Plus Medical Encyclopedia.
  3. McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York, NY: Scribner, 2004. p 367
  4. Foster, Steven, and Chongxi Yue. 1992. Herbal emissaries bringing Chinese herbs to the West : a guide to gardening, herbal wisdom, and well-being. Rochester, Vt: Healing Arts Press. Pages 134-38.
  5. Japanese Knotweed Alliance.
  6. Jones, Samuel B., and Arlene E. Luchsinger. 1979. Plant systematics. McGraw-Hill series in organismic biology. New York: McGraw-Hill. Page 254. ISBN 0-07032795-5
  7. McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York, NY: Scribner, 2004. p 366
  8. Wakefield Metropolitan District Council. Rhubarb. Retrieved 2006-03-12.. Retrieved June 9, 2008.
  9. Waters, Alice. Chez Panisse Fruit. New York, NY: Harper Collins, 2002. p 278