<unk>  is a perennial plant that grows from thick short rhizomes, comprising the genus Rheum. This genus is in the family Polygonaceae, along with dock, sorrel, knotweeds, knotgrasses and buckwheat.  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.<unk>  is actually a herb, but is often used in food as a fruit. In the United States until the 1940s it was considered a vegetable. It was reclassified as a fruit when US customs officials, baffled by the foreign food, decided it should be classified according to the way it was eaten.
Rhubarb
Triphenylmethane
Tetrachloroethylene
Dimethylcarbate
Nitrazine
Methyl tert-butyl ether
Vinylbital
Dicresyl