ABSTRACTBremiella sphaerosperma sp. nov.parasitic onImpatiensspp. (Balsaminaceae) is described from numerous specimens collected in northeastern North America, and two specimens collected in far eastern USSR.B. sphaerospermais partly sympatric withPlasmopara obducensand was confused with the latter in the past.Peronospora borreriae(Lagerh.) O. Const,comb. nov.(syn.Peronospora borreriaeLagerh.;Plasmopara cruseaeShaw&Safeeulla) parasitic on various Rubiaceae in Central and South America, is described and illustrated.