The extant herbarium material of the genus Lactarius (L. novoguineensis P.H
enn.) collected in tropical Papua New Guinean lowland forests is studied. I
n addition, four new taxa, L. leucophaeus, L. paleus, L. leoninus and L. wa
lleynii are introduced. A key to the five species, illustrations and discus
sion about their infrageneric position are presented.