Melampsora populnea is a rust fungus which causes pale orange-yellow, white edged swellings on Dogs Mercury and, less often, on Annual Mercury. These may reach up to 2 cm across. These are most often found on leaves and on swollen and distorted petioles, but may also affect the stems.
Woodland and shaded places where Dogs Mercury occurs.
Anytime while the host plants ae in leaf.
Status in Leicestershire and Rutland not known.
Leicestershire & Rutland Map
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