﻿AbstractThe specimen previously identified asMarsupellamicrophyllafrom Brazil is reassessed and described as a new species,M.brasiliensis. The new species is characterized by paroicous inflorescence, bispiral elaters, scale-like, commonly unlobed leaves and very small leaf cells. Descriptions and drawings are provided along with a corresponding discussion of the morphological peculiarity of the new species.Marsupellabrasiliensisbelongs to sect.Stolonicaulon, and the distribution ofMarsupellasect.Stolonicaulonin the New World is confirmed. The infrageneric position ofM.microphyllaremains unresolved, and whether it belongs to the same section is still unclear.