Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† sĕsĕlis, is, f., = σέσελις, a plant, meadow saxifrage, hartwort, seseli, Cic. N. D. 2, 50, 127; Plin. 8, 32, 50, § 112 sq.; 20, 22, 87, § 238.