A new γ-lactone derivative named davallialactone (4) and the 7-O-β-D-glucuronide of (±)-eriodictyol (5a) have been isolated from Davallia mariesii MOORE along with caffeic acid (1), 4-O-β-D-glucopyranosylcaffeic acid (2) and 4-O-β-D-glucopyranosyl-p-coumaric acid (3). The structures of the new compounds were determined by chemical and spectroscopic methods including two-dimensional nuclear magnetic resonance (2D NMR) techniques, especially ¹H-detected heteronuclear multiple-bond multiple-quantum coherence and long-range C-H J-resolved 2D NMR techniques.