Croton maasii (Euphorbiaceae), a new species from the western Amazon region

Croton maasii, a new species from South America, is described and illustrated. The species is only known from terra firme forests of the extreme western Amazonian region, in W Brazil and adjacent E Peru. Croton maasii resembles C. pachypodus, a more abundant and widely distributed species in the Neotropics, but differs from it in its much smaller fruits, foliage colour, less dense leaf indumentum, and a more even position of the petiolar glands.