Lion's leaf

Li´on's leaf`

    (lī´ŭnz lēf`)
n.1.(Bot.) A South European plant of the genus Leontice (Leontice leontopetalum), the tuberous roots of which contain so much alkali that they are sometimes used as a substitute for soap.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.