Plum Pocket Gall (on Black Cherry Tree)

These weird tongue-like galls emerging where immature cherries should be visible are probably the result of a fungal pathogen. The Tapthrina genus produces a number of fungi associated with leaf curling, pocket galls, and witch's broom. T. pruni in particular is known to produce distinctive tongue-like growth. The growth seen here is the distorted fruit, not the fungus itself.