One new species of Dorstenia from Brazil is described: D. carautae C.C. Berg, and four new combinations are made: D. cayapia Vellozo subsp. asaroides (Hooker) C.C. Berg, D. cayapia Vellozo subsp. paraguariensis (Hassler) C.C. Berg, D. cayapia Vellozo subsp. vitifolia (Gardner) C.C. Berg, and D. ramosa (Desvaux) Carauta, Valente & Sucre subsp. dolichocaula (Pilger) C.C. Berg. A list of and a key to the 22 Dorstenia species distinguished in south-eastern tropical America are presented, together with synonymy and distributional data.