Tropeolin or Tropaeolin: How To spell?

The word Tropeolin is misspelled against Tropaeolin, a noun meaning "A name given to any one of a series of orange-red dyestuffs produced artificially from certain complex sulphonic acid derivatives of azo and diazo hydrocarbons of the aromatic series; -- so called because of the general resemblance to the shades of nasturtium (Tropaeolum)."