AL'LIA'RIA. A genus of plants of the natural order Cruciferæ, closely allied to Sisymbrium and Erysimum, and ranked by some botanists in the genus Sisymbrium. It is known by the popular names of sauce-alone and jack-by-the-hedge. The best known species, Alliaria officinalis, or, as often commonly called, Sisymbrium alliaria, is a native of Great Britain, not unfrequently found on hedge-banks and in waste places in dry, rich soils, and is common in most parts of Europe. It has also become introduced in a number of places in the United States. It is a biennial, with a stem two to three feet high; large, stalked, heart-shaped leaves, white flowers, and pods much longer than their stalks, which are somewhat spreading. It seems more deserving of cultivation than many other plants which have long received the constant care of the gardener, being wholesome, nutritious, and to most persons pleasant. The powdered seeds were formerly employed as a sternutatory.