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 × cistena Prunus × cistena Prunus × cistena, the purple leaf sand cherry or dwarf red-leaf plum, is a hybrid species of prune-cherry, the result of a cross between "Prunus cerasifera" (cherry plum or myrobalan plum) and "Prunus pumila" (sand cherry). A leggy bush or shrubby tree, it typically reaches a height of 1.5–2.5 meters and has a useful life of 10–20 years. The fruit are edible, if strong-tasting. Some people make jams or preserves from them. It is not advisable to eat the pits. Frost-tolerant, purple leaf sand cherries can be grown up to USDA Hardiness Zone 2. Commercial specimens are