Rhubarb
Rhubarb is a
perennial plant that grows from thick, short
rhizomes, comprising the genus
Rheum. The large, somewhat triangular
leaf blades are elevated on long, fleshy petioles. The
flowers are small, greenish-white, and borne in large compound leafy inflorescences.
The plant is indigenous to
Asia, but is now grown in many areas, primarily for its fleshy petioles, commonly known as
rhubarb sticks. In temperate climate rhubarb is one of the first food plants to be ready for harvest, usually in April/May. The petioles can be cooked in a variety of ways. Stewed, they yield a tart sauce that can be eaten with sugar or used as filling for pies, tarts, and crumbles. This common use led to the
German slang term for rhubarb,
piestengel, or "pie plant."
Rhubarb is also used to make
wine.
During the winter it disappears completely and begins to grow 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 plant occurs in at least four species. 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.\nThe 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
Chinese Rhubarb (
R. palmatum).
Rhubarb is used as a strong
cathartic and for its tonic effect on the
mucous membranes of the
nasal cavity.
Toxic effects
\nRhubarb leaves contain poisonous substances. The exact chemistry is not well understood, but the LD50 for rhubarb leaves appears to be about 375mg/kg, or 5kg of rhubarb leaves for a 65kg human. The dose to cause sickness is, of course, much less.
External links and resources
\n* The Rhubarb Compendium http://www.rhubarbinfo.com/
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Category:Vegetables
