Source : Webster's Revised Unabridged Dictionary (1913)

Peucedanin \Peu*ced"a*nin\, n. (Chem.)
   A tasteless white crystalline substance, extracted from the
   roots of the sulphurwort ({Peucedanum}), masterwort
   ({Imperatoria}), and other related plants; -- called also
   {imperatorin}.

Masterwort \Mas"ter*wort`\, n. (Bot.)
   (a) A tall and coarse European umbelliferous plant
       ({Peucedanum Ostruthium}, formerly {Imperatoria}).
   (b) The {Astrantia major}, a European umbelliferous plant
       with a showy colored involucre.
   (c) Improperly, the cow parsnip ({Heracleum lanatum}).