Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ămărantus, i, m., = ἀμάραντος (unfading), amaranth: Celosia cristata, Linn.; Plin. 21, 8, 23, § 47; Tib. 3, 4, 33; Ov. F. 4, 439.