Heracleum lanatum

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]

from The Collaborative International Dictionary of English v.0.48

Cow parsnip \Cow" pars`nip\ (-n?p). (Bot.)
   A coarse umbelliferous weed of the genus {Heracleum}
   ({Heracleum sphondylium} in England, and {Heracleum lanatum}
   in America).
   [1913 Webster]