Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† arnoglossa, ae, f., = ἀρνόγλωσσον, a plant, sheep’s-tongue or plantain: Plantago major, Linn.; App. Herb. 1 (also called arnion; Isid., Orig. 17, 9, 50, calls it arnoglossos).