Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† phȳcos, i, n., = φῦκος, sea-weed, seawrack, = fucus, Plin. 13, 25, 48, § 135: phycos thalassion, rock-moss, orchil (pure Lat. fucus marinus), id. 26, 10, 66, § 103.