Aeciospore-surface structures of Phragmidium species parasitic on roses

Aeciospore-surface structures of Phragmidium species parasitic on roses were investigated by scanning electron microscopy. Seven kinds of structures were distinguished according to gross shape of ornamentations and their distribution on the aeciospore wall. The seven different structures were categorized into three major types: echinulate, annulate, and verrucose. The echinulate type was further classified into five types and designated in a numerical series, echinulate types 1–5. Application of the aeciospore-surface structures in the classification of Phragmidium species is discussed.