Taphrina pruni Taphrina pruni Taphrina pruni is a fungal plant pathogen of blackthorn (Prunus spinosa) that causes the Pocket or bladder Plum gall, a chemically induced distortion of the fruit (sloes), producing swollen on one side, otherwise deformed and flattened fruit gall without a stone. The twigs on infected plants may also be deformed with small strap-shaped leaves. "T. pruni" produces a distinctive tongue-like growth, similar to other closely related species such as "Taphrina alni" on Alder ("Alnus glutinosa") and "Taphrina padi" on Bird Cherry "Prunus padus". The growth is the distorted fruit and not a fungus in its entirety. "T. pruni"
Prunus cerasus Prunus cerasus Prunus cerasus (sour cherry, tart cherry, or dwarf cherry) is a species of "Prunus" in the subgenus "Cerasus" (cherries), native to much of Europe and southwest Asia. It is closely related to the sweet cherry ("Prunus avium"), but has a fruit that is more acidic. The tree is smaller than the sweet cherry (growing to a height of 4–10 m), has twiggy branches, and its crimson-to-near-black cherries are borne upon shorter stalks. There are several varieties of the sour cherry: the dark-red morello cherry and the lighter-red varieties including the amarelle cherry, and the popular Montmorency cherry. The