Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
hĕdĕra (ĕdĕra), ae, f., ivy, Hedera helix, Linn.; sacred to Bacchus, and hence wound around the thyrsus; also made into garlands with which poets were crowned, Plin. 16, 34, 62, § 144; Ov. F. 3, 767; id. M. 5, 338; Varr. ap. Serv. Verg. E. 7, 25; Verg. ib. 7, 38; 8, 13; id. G. 2, 258; Hor. C. 1, 1, 29; 1, 25, 17; id. Ep. 1, 3, 25; Juv. 7, 29 al.
In plur., Verg. E. 4, 19; id. G. 4, 124 al.