(Be forewarned. Parentheses lie ahead.)
Cercis siliquastrum, the Judas tree, is thought in folklore to be the kind of tree that Judas hanged himself after betraying Christ. While a number of linguists see this is a folk etymology based on a French phrase meaning "tree of Judea" the legend persists, not that the two ideas are mutually exclusive. Whether or not Judas Iscariot hanged himself from this tree, or any tree, or in fact was really the betrayer of Jesus, the name has a certain Biblical resonance, and there's a slight aura of Christian allegory to this episode. In that it feels like an Ellery Queen novel, some of which took on an allegorical role after Manfred B. Lee's conversion from Judaism to Episcopal Christianity.
(Jonathan Creek has also taken a title from the Judas tree.