Lewis & Short

mĕlanthĭum (-on), ii, n., = μελάνθιον, the plant gith, cultivated fennel-flower: gith e Graecis alii melanthion, alii melaspermon, vocant, Plin. 20, 17, 71, § 182; Col. poët. 10, 245; also chamomile, Plin. 22, 21, 26, § 53.
Called also mĕlanthum, Ser. Samm. 30.