imperatoria

from The Collaborative International Dictionary of English v.0.48

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}).
       [1913 Webster]