Bulgaria inquinans is a fungus in the family Bulgariaceae. It is commonly known by the name black bulgar.
It grows on branches and bark of dead oak and hornbeam. The species can be found from October to March. It can be commonly found on felled trees stored in timber yards. Research into the colouring materials found in the fungus by H.Lockett and R.Edwards at Bradford University gave name to three purple pigments as two bulgarhodins and bulgarein.