Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† prūnus, i, f., = προύνη, a plum-tree, Verg. G. 2, 34; Plin. 13, 10, 19, § 65; Pall. Nov. 7, 14; id. Feb. 25, 32.
Esp.: prunus silvestris, the blackthorn, sloe-tree, Col. 2, 2, 20; Plin. 18, 6, 7, § 34.