Circumscribed. Mostly conspicuous and much thickened leaf-concavities, c. 1 cm. across, bright red and yellow-margined above, pinkish white, eventually hymenium-clad and chalk-white beneath. Sometimes mere leaf-spots; occasionally strongly hypertrophied and badly malformed flower-buds or shoot-tips.
”- Nannfeldt, J.A.: (1981) Exobasidium, a taxonomic reassessment applied to the European species©