Everything about Rhubarb totally explained
Rheum is a genus of
perennial plants that grow from thick short
rhizomes. The genus is in the family Polygonaceae, and includes the vegetable rhubarb (
Rheum rhabarbarum or
Rheum x hybridum.) The plants have large
leaves that are somewhat triangular shaped with long fleshy
petioles. The
flowers are small, greenish-white to rose-red, and born in large compound leafy
inflorescences. A number of varieties of rhubarb have been domesticated both as medicinal plants and for human consumption. While the leaves are toxic, the stems are used in pies and other foods for their tart flavor.
Species
The genus is represented by about 60 extant species. Among species found in the wild, those most commonly used in cooking are the
Garden Rhubarb (
R. rhabarbarum) and
R. rhaponticum, which, though a true rhubarb, bears the common name False Rhubarb. 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
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.
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.
Description
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're 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
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. 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.
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.
Depending on the variety and production technique the content of
anthocyanins in the stalks can vary, yielding a color palate from the commonly associated deep red through speckled pink to simply green. The green-stalked rhubarb is more robust and has a higher yield, though the red-colored stalks are more popular with consumers. The stalk's color isn't related to its suitability for cooking.
(External Link
) Rhubarb is ready to be consumed as soon as it's harvested, and freshly cut stalks will be firm and glossy.
The
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, a practice that produces a sweeter, more tender stalk.
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 leaves contain
poisonous substances. Rhubarb leaves contain
oxalic acid, a
corrosive and
nephrotoxic acid that's present in many plants. The (median lethal dose) for pure oxalic acid is predicted to be about 375
mg/
kg body weight, 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%, so a rather unlikely five kilograms of the extremely sour leaves would have to be consumed to reach an dose of oxalic acid. However, the leaves are believed to also contain an additional, unidentified toxin. In the petioles, the amount of oxalic acid is much lower, only about 2-2.5% of the total acidity, especially when harvested before mid-June (in the northern hemisphere), but it's still enough to cause slightly rough teeth.
The roots have been used as strong laxative for over 5,000 years. 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.
Other uses of the word
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. 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, 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.
"Donkey Rhubarb" refers to
Japanese knotweed and is also the name of
an EP by
Aphex TwinFurther Information
Get more info on 'Rhubarb'.
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