What is "rumex crispus"

Rumicin \Ru"mi*cin\, n. (Chem.) A yellow crystalline substance found in the root of yellow dock ( Rumex crispus) and identical with chrysophanic acid.

Dock \Dock\ (d[o^]k), n. [AS. docce; of uncertain origin; cf. G. docken-bl["a]tter, Gael. dogha burdock, OF. doque; perh. akin to L. daucus, daucum, Gr. ?, ?, a kind of parsnip or carrot, used in medicine. Cf. Burdock.] (Bot.) A genus of plants ( Rumex), some species of which are well-known weeds which have a long taproot and are difficult of extermination.

Note: Yellow dock is Rumex crispus, with smooth curly leaves and yellow root, which that of other species is used medicinally as an astringent and tonic.

Rumex crispus, the curly dock, curled dock or yellow dock, is a perennial flowering plant in the family Polygonaceae, native to Europe and Western Asia.