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 avium in classical schools, it must once more be said that cherry trees (at least the bird cherry) existed in Italy before Lucullus, and that the famous gourmet did not need to go far to seek the species with the sour or bitter fruit. De Candolle suggests that what Lucullus brought back was a particular cultivar of "Prunus avium" from the Caucasus. The origin of cultivars of "P. avium" is still an open question. Modern cultivated cherries differ from wild ones in having larger fruit, 2–3 cm diameter. The trees are often grown on dwarfing rootstocks to keep them smaller for