Phylum: Basidiomycota Family: Pucciniaceae
Uromyces dactylidis G.H. Otth
Celandine Clustercup Rust
Common on the leaves of Lesser Celandine Ranunculus ficaria from March to June. Alternate hosts are Dactylis, Poa and Festuca rubra
References:
Ellis & Ellis (1997) - Microfungi on Land Plants
Termorshuizen & Swertz - Dutch Rust Fungi