Summary
In this paper the autor discribes a new species of Masdevallia (Orchidaceae) from amazoniam region. Now the number of species of that genus extendes to nine in this region. The new species M. osmariniana, differes mainly from the nearest species, M. o'brieniana in the linear-lanceolate leaves, petals 2-venoses, unguiculo costulated, lip apex denticulate, column with auricles erose in the base and corniculate at the apex and. finally, by clinandrium at the apex bipartite.