Phylum: Basidiomycota Family: Pucciniastraceae
Melampsoridium betulinum (Pers.) Kleb.
As the name suggest, its main host for the uredinal stage is the Betula genus, but its also attacks Alnus species. The aecial stage occurs on Larix. Very common and can be a problem in commercial plantations
Ellis & Ellis (1997) - Microfungi on Land Plants
Termorshuizen & Swertz (2011) - Dutch Rust Fungi
Wilson & Henderson (2011 reprint) - British Rust Fungi