Rhubarb belongs to the family of the thousandknots(Polygonaceae). The Chinese people has found the plant from out the desert of Azia and put her on the mountainfalls of the chinese imperium. This plant was cultured for his root, from which a very strong purgative was made. There is still cultured chinese rhubarb fur this purpose(also in the Nedtherlands).
Different, more ore less important rhubarb-varieties are:
Palmatum L. (Chinese or Russian rhubarb), original from China. Leaves are very deep cut in with in pointed slips splitted margin, flowers are yellowwhite.
Rheum Officinale Baill. (Teethed rhubarb), original from Tibet. Leaves flat, with roughteethed margin, now and than cut in deeper. Young leaves of the plumeflower hang over. Flowers are whity.
Rheum Emodi Wall.(Star rhubarb), original from Himalaya-rigion. Leaves with some up and down curved margin. Leafststalks are on top hollow, at the bottum round. Flowers whity.
Rhaponticum L. (Blunt rhubarb), original from South-Siberian. Leaves with some up and down curved margin. Leafststalks are on top flat, at the bottum furrowed. Flowers yellow or yellowwhite.
Undulatum L. (Curved rhubarb), original from China. Leaves with almost frizzled margin(like a frizzle-cabbage but than less cut in so stark). Leafststalks are on top flat, at the bottum with sharp sides. Flowers yellowwhite.
Rheum Palmatum and Rheum Officinale are cultured for the root.
Rheum Rhaponticum and Rheum Undulatum is cultured for the leafstalks.