Undiferentiated or Undifferentiated: How To spell?

The word Undiferentiated is misspelled against Undifferentiated, an adjective meaning "Not differentiated; specifically (Biol.), homogenous, or nearly so; -- said especially of young or embryonic tissues which have not yet undergone differentiation (see Differentiation, 3), that is, which show no visible separation into their different structural parts."