What is "erysimum cheiranthoides"

Mustard \Mus"tard\, n. [OF. moustarde, F. moutarde, fr. L. mustum must, -- mustard was prepared for use by being mixed with must. See Must, n.]

1. (Bot.) The name of several cruciferous plants of the genus Brassica (formerly Sinapis), as white mustard ( Brassica alba), black mustard ( Brassica Nigra), wild mustard or charlock ( Brassica Sinapistrum).

   Note: There are also many herbs of the same family which are called mustard, and have more or less of the flavor of the true mustard; as, bowyer's mustard ( Lepidium ruderale); hedge mustard ( Sisymbrium officinale); Mithridate mustard ( Thlaspi arvense); tower mustard ( Arabis perfoliata); treacle mustard ( Erysimum cheiranthoides).

2. A powder or a paste made from the seeds of black or white mustard, used as a condiment and a rubefacient. Taken internally it is stimulant and diuretic, and in large doses is emetic.

   Mustard oil (Chem.), a substance obtained from mustard, as a transparent, volatile and intensely pungent oil. The name is also extended to a number of analogous compounds produced either naturally or artificially.

Treacle \Trea"cle\ (tr[=e]"k'l), n. [OE. triacle a sovereign remedy, theriac, OF. triacle, F. th['e]riaque (cf. Pr. triacla, tiriaca, Sp. & It. triaca, teriaca), L. theriaca an antidote against the bite of poisonous animals, Gr. ?, fr. ? of wild or venomous beasts, fr. qhri`on a beast, a wild beast, dim. of qh`r a beast. Cf. Theriac.]

1. (Old Med.) A remedy against poison. See Theriac, 1.

   We kill the viper, and make treacle of him.
   --Jer. Taylor.

2. A sovereign remedy; a cure. [Obs.]

   Christ which is to every harm treacle.
   --Chaucer.

3. Molasses; sometimes, specifically, the molasses which drains from the sugar-refining molds, and which is also called sugarhouse molasses.

   Note: In the United States molasses is the common name; in England, treacle.

4. A saccharine fluid, consisting of the inspissated juices or decoctions of certain vegetables, as the sap of the birch, sycamore, and the like.

   Treacle mustard (Bot.), a name given to several species of the cruciferous genus Erysimum, especially the Erysimum cheiranthoides, which was formerly used as an ingredient in Venice treacle, or theriac.

   Treacle water, a compound cordial prepared in different ways from a variety of ingredients, as hartshorn, roots of various plants, flowers, juices of plants, wines, etc., distilled or digested with Venice treacle. It was formerly regarded as a medicine of great virtue.
   --Nares.

   Venice treacle. (Old Med.) Same as Theriac, 1.

Erysimum cheiranthoides (treacle-mustard or wormseed wallflower) is a species of Erysimum native to most of central and northern Europe and northern and central Asia.