Difference between revisions of "Rhubarb" - New World Encyclopedia

From New World Encyclopedia
 
(25 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 +
{{Images OK}}{{Submitted}}{{Approved}}{{Copyedited}}
 
{{Taxobox
 
{{Taxobox
 
| name = Rhubarb
 
| name = Rhubarb
Line 18: Line 19:
 
* ''[[Rheum rhaponticum]]''
 
* ''[[Rheum rhaponticum]]''
 
}}
 
}}
'''Rhubarb''' is the common name for [[perennial]] [[plant]]s 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 are characterized by
+
'''Rhubarb''' is the common name for [[perennial]] [[plant]]s 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 [[rhizome]]s and are characterized by large [[leaf|leaves]] that are somewhat triangular shaped, small [[flower]]s grouped in large, compound, leafy [[inflorenscene]]s, and long fleshy [[Petiole (botany)|petiole]]s.
  
Other cultivated rhubarbs include  
+
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).
  
 +
The rhubarb represents an aspect of human [[creativity]]. The leaves themselves are toxic, the stalks themselves have an intense tartness. However, combining them with a [[sugar]] makes a delicious food with a unique flavor that can be used in sauces, desserts, and jams, and is so popular for pies that rhubarb in some regions is known as "pieplant" (Herbst 2001). Rhubarb may also be combined with [[strawberry|strawberries]] (a traditional flavor combination in the United States) or with [[ginger]] (Herbst 2001).
  
 +
==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.
  
is a genus of [[perennial plant]]s that grow from thick short [[rhizome]]s. The genus is in the family Polygonaceae, and includes the vegetable rhubarb (''Rheum rhabarbarum'' or ''Rheum x hybridum''.The plants have large [[leaf|leaves]] that are somewhat triangular shaped with long fleshy [[Petiole (botany)|petiole]]s. The [[flower]]s are small, greenish-white to rose-red, and grouped in large compound leafy [[inflorescence]]s.  A number of varieties of rhubarb have been domesticated both as medicinal plants and for human consumption.  While the leaves are toxic, the stalks are used in pies and other foods for their tart flavor.
+
[[Image:Rhubarb flower.JPG|thumb|left|200px|Rhubarb flower.]]
 +
[[Leaf|Leaves]] of [[Polygonoideae]] are simple, arranged alternately on the stems, and have a peculiar pair of sheathing [[stipule]]s 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 three or six 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 three to eight 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 two to four stigmas are produced (Jones and Luchsinger 1979).
 +
 
 +
[[Image:Rabarber stelen.jpg|thumb|right|Rhubarb growing]]
 +
'''''Rheum''''', the rhubarb genus, is a [[genus]] of [[flowering plant]]s that grow from thick short [[rhizome]]s. ''Rheum'' species are [[herbaceous]] perennials with hermaphrodite flowers, consisting of a colored perianth, composed of six to nine segments, arranged in two rows. The [[flower]]s 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 [[seed]]s are albuminous and have straight [[embryo]]s. The plants have large [[leaf|leaves]] that are somewhat triangular shaped with long fleshy [[Petiole (botany)|petiole]]s. The [[celery]]-like stalks can vary from deep red to red, with pink or speckled in between.  
  
 
==Species==
 
==Species==
  
The genus 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 [[Rheum rhabarbarum|Garden Rhubarb]] (''R. rhabarbarum'') and ''[[Rheum rhaponticum|R. rhaponticum]]'', which, though a true rhubarb, bears the common name False Rhubarb (ITIS). The many varieties of cultivated rhubarb more usually grown for eating are recognised as ''Rheum x hybridum'' in the Royal Horticultural Societies list of recognised plant names. The drug rheum is prepared from the rhizomes and [[root]]s of another species, ''[[Rheum officinale|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 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 [[Rheum rhabarbarum|"garden rhubarb"]] ''(R. rhabarbarum)'' (ITIS 1999b) and ''[[Rheum rhaponticum|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.  
  
''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]].
+
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]].
  
==Description==
+
''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]].
[[Image:Rabarber stelen.jpg|thumb|right|Rhubarb growing]]
 
''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 have nine stamina inserted on the torus at the base of the peranthium, they 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, the seeds are albuminous and have straight embryos.
 
  
==Cultivation and consumption==
+
==History, cultivation, and consumption==
 
[[Image:Rhubarb07.JPG|right|thumb|Rhubarb displayed for sale at a grocery]]
 
[[Image:Rhubarb07.JPG|right|thumb|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 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, 366).  
  
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.
+
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 seventeenth-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 et al. 2002).
  
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.[http://www.rhubarbinfo.com/rhubarb-varieties.html]: The green-stalked rhubarb is more robust and has a higher yield, and the red-colored stalks are more popular with consumers.
+
[[Image:Shucked and sliced up rhubarb.jpg|thumb|left|200px|Shucked and sliced up rhubarb]]
 +
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]].  
  
The stalks, which are [[Petiole (botany)|petiole]]s, 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 [[pie]]s (see [[rhubarb pie]]), [[tart]]s, and [[crumble]]s. This common use led to the slang term for rhubarb, '''"pie plant"'''. Cooked with [[Strawberry|strawberries]] or apples as a sweetener, or with stem or root [[ginger]], rhubarb makes excellent jam. It can also be used to make [[country wine|wine]] and as an ingredient in baked goods.  
+
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 United States, 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.
  
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 [[United Kingdom|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, West Yorkshire|Morley]] (Wakefield), a practice that produces a sweeter, more tender stalk (McGee 2004, p. 367).
+
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 (RC 2004). The green-stalked rhubarb is more robust and has a higher yield, and the red-colored stalks are more popular with consumers.
  
 
[[Image:Rhubarb Pie.jpg|thumb|right|A homemade rhubarb pie]]
 
[[Image:Rhubarb Pie.jpg|thumb|right|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.
+
The stalks, which are [[Petiole (botany)|petiole]]s, 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 [[pie]]s, [[tart]]s, and [[crumble]]s. This common use led to the slang term for rhubarb, "pie plant." Cooked with [[Strawberry|strawberries]] or [[apple]]s as a sweetener, or with stem or root [[ginger]], rhubarb makes excellent [[jam]]. It can also be used to make [[country wine|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 [[United Kingdom|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, West Yorkshire|Morley]] (Wakefield), a practice that produces a sweeter, more tender stalk (McGee 2004, 367).
 +
 
 +
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 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 membrane]]s of the mouth and the [[nasal cavity]].
+
Rhubarb is used as a strong [[laxative]] and for its [[astringent]] effect on the [[mucous membrane]]s of the mouth and the [[nasal cavity]]. The roots have been used as strong laxative for over 5,000 years (Foster and Yue 1992). The roots and stems are rich in [[anthraquinone]]s, such as [[emodin]] and [[rhein]]. These substances are [[cathartic]] and laxative.
  
 
==Toxic effects==
 
==Toxic effects==
[[Image:Rhubarb 01.jpg|thumb|Rhubarb]]
 
[[Image:Rhubarb flower.JPG|thumb|Rhubarb flower.]]
 
  
Rhubarb leaves contain [[poison]]ous substances. Rhubarb leaves contain [[oxalic acid]], a [[corrosive]] and [[nephrotoxic]] acid that is present in many plants. The {{LD50}} (median lethal dose) for pure oxalic acid is predicted to be about 375 [[milligram|mg]]/[[kilogram|kg]] [[body weight]],{{Fact|date=July 2007}} or about 25 [[gram|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%,<ref>GW Pucher, AJ Wakeman, HB Vickery. ''[http://www.jbc.org/cgi/content/citation/126/1/43 THE ORGANIC ACIDS OF RHUBARB (RHEUM HYBRIDUM). III. THE BEHAVIOR OF THE ORGANIC ACIDS DURING CULTURE OF EXCISED LEAVES.]'' Journal of Biological Chemistry, 1938</ref> so a rather unlikely five kilograms of the extremely sour leaves would have to be consumed to reach an {{LD50}} dose of oxalic acid. However, the leaves are believed to also contain an additional, unidentified toxin.<ref>{{cite web | url=http://www.nlm.nih.gov/medlineplus/ency/article/002876.htm | title=Rhubarb leaves poisoning | work=Medline Plus Medical Encyclopedia}}</ref> In the petioles, the amount of oxalic acid is much lower, only about 2-2.5% of the total acidity<ref>McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen.  New York, NY: Scribner, 2004. p 367</ref>, especially when harvested before mid-June (in the northern hemisphere), but it is still enough to cause slightly rough teeth.{{Fact|date=July 2007}}
+
Rhubarb leaves contain [[poison]]ous substances. Specifically, they contain [[oxalic acid]], a [[corrosive]] and [[nephrotoxic]] acid that is present in many plants. The LD50 (median lethal dose) for pure oxalic acid is predicted to be about 375 milligrams per kilogram body weight, or about 25 grams fro a 65 kilogram (~140 pound) human. While the oxalic acid content of rhubarb leaves can vary, a typical value is about 0.5 percent (Pucher et al. 1938), so a rather unlikely five kilograms of the extremely sour leaves would have to be consumed to reach an LD50 dose of oxalic acid. However, the leaves are believed to also contain an additional, unidentified toxin (Perez 2006).
  
The roots have been used as strong laxative for over 5,000 years.<ref>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.</ref> The roots and stems are rich in [[anthraquinone]]s, such as [[emodin]] and [[rhein]]. These substances are [[cathartic]] and [[laxative]], which explains the sporadic abuse of Rhubarb as a [[dieting|slimming]] agent. Anthraquinones are yellow or orange and may colour the [[urine]].{{Fact|date=July 2007}}
+
In the petioles, the amount of oxalic acid is much lower, only about 2 to 2.5 percent of the total acidity (McGee 2004), especially when harvested before mid-June (in the northern hemisphere).
  
==Other uses of the word==
+
==References==
[[Image:Shucked and sliced up rhubarb.jpg|thumb]]
+
* Foster, S., and C. Yue. 1992. ''Herbal Emissaries Bringing Chinese Herbs to the West: A Guide to Gardening, Herbal Wisdom, and Well-being.'' Rochester, Vt: Healing Arts Press. ISBN 0892813490.
It is or was common for a crowd of [[Extra (actor)|extra]]s 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 [[United States|American]] equivalent is [[walla]].
+
 
 +
* Herbst, S.T. 2001. ''The New Food Lover's Companion: Comprehensive Definitions of Nearly 6,000 Food, Drink, and Culinary Terms. Barron's Cooking Guide.'' Hauppauge, NY: Barron's Educational Series. ISBN 0764112589.
  
Possibly from this usage, possibly from a variant on "[[Reubens|rube]]", or perhaps some of both, the word also denotes a loud argumentThe term has been most commonly used in [[baseball]].
+
* Integrated Taxonomic Information System (ITIS). 1999a. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=21318 ''Rheum'' L.]. ''ITIS Taxonomic Serial No.: 21318''. Retrieved June 9, 2008.  
  
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".
+
* &mdash;. 1999b. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=504747 ''Rheum rhabarbarum'' L.] ''ITIS Taxonomic Serial No.: 504747''. Retrieved June 9, 2008.  
[[Image:Rheumaustrale.jpg|thumb|left|[[Fruit]]s]]
 
In the 1989 film ''[[Batman (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 (play)|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.
+
* &mdash;. 1999c. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=21319 ''Rheum rhaponticum'' L.]. ''ITIS Taxonomic Serial Number 21319''. Retrieved June 9, 2008.  
  
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.{{Fact|date=July 2007}} 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]].
+
* &mdash;. 1999d. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=506563 ''Rheum officinale'' Baillon]. ''ITIS Taxonomic Serial No.: 506563''. Retrieved June 9, 2008.  
  
In Canada, the phrase "putting it in the rhubarb" describes driving a vehicle off the road, possibly into roadside vegetation.
+
* &mdash;. 1999e. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=506564 ''Rheum palmatum''  L.]. ''ITIS Taxonomic Serial No.: 506564''. Retrieved June 9, 2008.  
  
"Donkey Rhubarb" refers to [[Japanese knotweed]]<ref>{{cite web | url=http://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm | title=Japanese Knotweed Alliance}}</ref> and is also the name of [[Donkey_Rhubarb_(EP)|an EP]] by [[Aphex Twin]]
+
* Jones, S. B., and A. E. Luchsinger. 1979. ''Plant Systematics''. New York: McGraw-Hill. ISBN 0070327955.
  
==References==
+
* McGee, H. 2004. ''On Food and Cooking: The Science and Lore of the Kitchen''. New York, NY: Scribner. ISBN 0684800012.
{{reflist}}
 
  
 +
* Perez, E. 2006. [http://www.nlm.nih.gov/medlineplus/ency/article/002876.htm Rhubarb leaves poisoning]. ''Medline Plus''. Retrieved June 9, 2008.
  
* Integrated Taxonomic Information System (ITIS). n.d. [http://itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=21319 ''Rheum rhaponticum'' L.]. ''ITIS Taxonomic Serial Number 21319''. Retrieved June 9, 2008.  
+
* Pucher, G. W., A. J. Wakeman, and H. B. Vickery. 1938. [http://www.jbc.org/cgi/reprint/126/1/43 The Organic acids of rhubarb ''(Rheum hybridum)''. III. The behavior of the organic acids during culture of excised leaves.] ''Journal of Biological Chemistry'' 126(1): 43-54. Retrieved June 9, 2008.
  
<ref>McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York, NY: Scribner, 2004. p 366</ref> 
+
* Rhubarb Compendium (RC). 2004. [http://www.rhubarbinfo.com/rhubarb-varieties.html Rhubarb varieties]. ''Rhubarb Compendium''. Retrieved June 9, 2008.  
  
<ref name="wgur">{{cite web | author = Wakefield Metropolitan District Council | url = http://www.wakefield.gov.uk/CultureAndLeisure/HistoricWakefield/Rhubarb/default.htm | title = Rhubarb | accessdate = 2006-03-12}}. Retrieved June 9, 2008.</ref>
+
* Wakefield Metropolitan District Council. [http://www.wakefield.gov.uk/CultureAndLeisure/HistoricWakefield/Rhubarb/default.htm Rhubarb]. ''Wakefield Metropolitan District Council''. Retrieved June 9, 2008.
  
 
* Wang, A., M. Yang, and J. Liu. 2005. [http://aob.oxfordjournals.org/cgi/content/abstract/96/3/489 Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus ''Rheum'' (Polygonaceae) inferred from chloroplast DNA trnL-F sequences]. ''Annals of Botany'' 96(3): 489-498. Retrieved June 9, 2008.
 
* Wang, A., M. Yang, and J. Liu. 2005. [http://aob.oxfordjournals.org/cgi/content/abstract/96/3/489 Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus ''Rheum'' (Polygonaceae) inferred from chloroplast DNA trnL-F sequences]. ''Annals of Botany'' 96(3): 489-498. Retrieved June 9, 2008.
  
<ref>Waters, Alice. Chez Panisse Fruit. New York, NY: Harper Collins, 2002. p 278</ref>
+
* Waters, A., A. Tangren, and F. Streiff. 2002. ''Chez Panisse Fruit''. New York, NY: Harper Collins. ISBN 0060199571.
 
 
==External links==
 
  
* [http://www.rhubarbinfo.com/ The Rhubarb Compendium]
 
* [http://www.bbc.co.uk/food/recipes/mostof_forcedrhubarb.shtml History of "Forced Rhubarb"]
 
* [http://news.bbc.co.uk/2/hi/uk_news/magazine/6474741.stm Just what is "Yorkshire forced indoor rhubarb"?]
 
* [http://www.washingtonwinemaker.com/blog/2008/01/23/rhubarb-wine-recipe/ A Rhubarb Wine Recipe]
 
* [http://www.rhubarb-recipes.com/ 150 Free Rhubarb Recipes]
 
  
 
[[Category:Life sciences]]
 
[[Category:Life sciences]]
 
[[Category:Plants]]
 
[[Category:Plants]]
  
{{credit|Rhubarb&oldid=217891324}}
+
{{credit|Rhubarb|217891324|Polygonaceae|207093546}}

Latest revision as of 09:17, 10 August 2022

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).

The rhubarb represents an aspect of human creativity. The leaves themselves are toxic, the stalks themselves have an intense tartness. However, combining them with a sugar makes a delicious food with a unique flavor that can be used in sauces, desserts, and jams, and is so popular for pies that rhubarb in some regions is known as "pieplant" (Herbst 2001). Rhubarb may also be combined with strawberries (a traditional flavor combination in the United States) or with ginger (Herbst 2001).

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.

Rhubarb flower.

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 three or six 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 three to eight 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 two to four 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. The celery-like stalks can vary from deep red to red, with pink or speckled in between.

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.

History, cultivation, and consumption

Rhubarb displayed for sale at a grocery

Rhubarb 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, 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 seventeenth-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 et al. 2002).

Shucked and sliced up rhubarb

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 United States, 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 (RC 2004). The green-stalked rhubarb is more robust and has a higher yield, and the red-colored stalks are more popular with consumers.

A homemade rhubarb pie

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, 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, 367).

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. The roots have been used as strong laxative for over 5,000 years (Foster and Yue 1992). The roots and stems are rich in anthraquinones, such as emodin and rhein. These substances are cathartic and laxative.

Toxic effects

Rhubarb leaves contain poisonous substances. Specifically, they contain oxalic acid, a corrosive and nephrotoxic acid that is present in many plants. The LD50 (median lethal dose) for pure oxalic acid is predicted to be about 375 milligrams per kilogram body weight, or about 25 grams fro a 65 kilogram (~140 pound) human. While the oxalic acid content of rhubarb leaves can vary, a typical value is about 0.5 percent (Pucher et al. 1938), so a rather unlikely five kilograms of the extremely sour leaves would have to be consumed to reach an LD50 dose of oxalic acid. However, the leaves are believed to also contain an additional, unidentified toxin (Perez 2006).

In the petioles, the amount of oxalic acid is much lower, only about 2 to 2.5 percent of the total acidity (McGee 2004), especially when harvested before mid-June (in the northern hemisphere).

References
ISBN links support NWE through referral fees

  • Foster, S., and C. Yue. 1992. Herbal Emissaries Bringing Chinese Herbs to the West: A Guide to Gardening, Herbal Wisdom, and Well-being. Rochester, Vt: Healing Arts Press. ISBN 0892813490.
  • Herbst, S.T. 2001. The New Food Lover's Companion: Comprehensive Definitions of Nearly 6,000 Food, Drink, and Culinary Terms. Barron's Cooking Guide. Hauppauge, NY: Barron's Educational Series. ISBN 0764112589.
  • 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.
  • Jones, S. B., and A. E. Luchsinger. 1979. Plant Systematics. New York: McGraw-Hill. ISBN 0070327955.
  • McGee, H. 2004. On Food and Cooking: The Science and Lore of the Kitchen. New York, NY: Scribner. ISBN 0684800012.
  • Rhubarb Compendium (RC). 2004. Rhubarb varieties. Rhubarb Compendium. Retrieved June 9, 2008.
  • Wakefield Metropolitan District Council. Rhubarb. Wakefield Metropolitan District Council. Retrieved June 9, 2008.
  • Waters, A., A. Tangren, and F. Streiff. 2002. Chez Panisse Fruit. New York, NY: Harper Collins. ISBN 0060199571.

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.