The Collaborative International Dictionary of English v.0.48:

Melampyrin \Mel`am*py"rin\, Melampyrite \Mel`am*py"rite\, n.
   [NL. Melampyrum cowwheat; Gr. me`las black + pyro`s wheat.]
   (Chem.)
   The saccharine substance dulcite; -- so called because found
   in the leaves of cowwheat (Melampyrum). See Dulcite.
   [1913 Webster]