Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† hēmĭŏnĭon, ĭi, n., = ἡμιόνιον, a plant, called also asplenum, Asplenium hemionitis, Linn.; Plin. 27, 5, 17, § 34; App. Herb. 56.