Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† asplēnum or -on, i, n., = ἄσπληνον, miltwort, spleenwort: Asplenum ceterach, Linn.: Asplenon sunt qui hemionion vocant, Plin. 27, 5, 17, § 34; in Vitr. 1, 4, written as Greek, and in Isid. Orig. 17, 9, 87, asplenos.