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 pumila leathery, long, with a serrated margin. The flowers are in diameter with five white petals and 25–30 stamens. They are produced in small clusters of two to four. The fruit is a small cherry diameter, ripening dark purple in early summer. "Prunus × cistena" (purple leaf sand cherry) is a hybrid of "Prunus cerasifera" (Cherry Plum) and "Prunus pumila". It was developed by Niels Ebbesen Hansen of South Dakota State University in 1910. Prunus pumila Prunus pumila, commonly called sand cherry, is a North American species of cherry in the rose family. It is widespread in eastern and central Canada