Taphrina padi Taphrina padi Taphrina padi is a fungal plant pathogen that induces the form of pocket plum gall that occurs on Bird Cherry ("Prunus padus"). The gall is a chemically induced distortion of the fruits, which are swollen, hollow, curved and greatly elongated, without a seed or stone, but retaining the style. The twigs on infected plants may also be deformed with small strap-shaped leaves. "Taphrina padi", a 'tongue fungus', produces a distinctive, elongated, tongue-like growth on Bird Cherry, similar to other closely related species such as "Taphrina alni" on Alder ("Alnus glutinosa") and "Taphrina pruni" on Blackthorn ("Prunus spinosa"). The
Prunus americana Prunus americana Prunus americana, commonly called the American plum, wild plum, or Marshall's large yellow sweet plum, is a species of "Prunus" native to North America from Saskatchewan and Idaho south to New Mexico and east to Québec, Maine and Florida. "Prunus americana" has often been planted outside its native range and sometimes escapes cultivation. It is commonly confused with the Canada plum ("Prunus nigra"), although the fruit is smaller and rounder and bright red as opposed to yellow. Many cultivated varieties have been derived from this species. It forms an excellent stock upon which to graft the domestic plum.