Dorstenia romaniucii A. Ferreira & M. D. M. Vianna (Moraceae) is described and illustrated as a new species, similar to the Atlantic Forest species D. turnerifolia Fisch. & C. A. Mey and distinguished by oval marginal bracts in two rows and intermixed flowers in the inflorescence. The classification of D. romaniucii along with D. turnerifolia clearly lies with species of Dorstenia sect. Lecania based on their elongated internodes allied to subulate stipules and suffrutescent habit. Dorstenia romaniucii is known only from Espirito Santo state, southeastern Brazil and is designated as a critically endangered species because its extent of occurrence is estimated to be less than 100 Km² in an extremely fragmented area, in the Atlantic Forest domain.