Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† scammōnĕa, ae, f., = σκαμμωνία, scammony, Cic. Div. 1, 10, 16; Plin. 25, 5, 22, § 54.
Also scammōnĕum, i, n., Cato, R. R. 157, 12: scammōnĭa, ae, f., Plin. 26, 8, 58, § 90; 26, 9, 60, § 93; Veg. 3, 6, 9; Scrib. Comp. 140: scammōnĭum, i, n., Plin. 26, 8, 38, § 59.
scammōnĭa, ae, v. scammonea.