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 subg. Padus "Padus" is polyphyletic and is therefore invalid as a genus, subgenus or anything else. In Finland and Sweden, the blooming of bird cherry ("Prunus padus", Finnish "tuomi") signifies the start of the summer for many people. In southern Finland, this normally takes place during the two last weeks of May or very early June. North Dakota State University agriculture information page about "Prunus virginiana" Prunus subg. Padus Prunus" subg. "Padus (bird cherries) is a subgenus of "Prunus", characterised by having deciduous leaves, flowers 12-30 together on slender racemes produced in late spring well after leaf emergence, and small, sour fruit