The Collaborative International Dictionary of English v.0.48:

Frumentaceous \Fru"men*ta"ceous\, a. [L. frumentaceus, fr.
   frumentum corn or grain, from the root of frux fruit: cf. F.
   frumentac['e]. See Frugal.]
   Made of, or resembling, wheat or other grain.
   [1913 Webster]