Source : Webster's Revised Unabridged Dictionary (1913)

Lion's leaf \Li"on's leaf`\ (l[imac]"[u^]nz l[=e]f`). (Bot.)
   A South European plant of the genus {Leontice} ({L.
   leontopetalum}), the tuberous roots of which contain so much
   alkali that they are sometimes used as a substitute for soap.