Phylum: Basidiomycota Family: Uropyxidaceaea
Tranzschelia anemones (Pers.) Nannf.
As the specific names suggests, this is a rust predominantly found on Wood Anemone Anemone nemarosa but also found on Thalictrum
References:
Termorshuizen & Swertz (2011) - Dutch Rust Fungi
Ellis & Ellis - Microfungi on Miscellaneous Substrates