Fumaric \Fu*mar"ic\, a. (Chem.) Pertaining to, or derived from, fumitory (Fumaria officinalis).

Fumaric acid (Chem.), a widely occurring organic acid, exttracted from fumitory as a white crystallline substance, C2H2(CO2H)2, and produced artificially in many ways, as by the distillation of malic acid; boletic acid. It is found also in the lichen, Iceland moss, and hence was also called lichenic acid.

Source: Webster's Revised Unabridged Dictionary (1913)