The genus Splachnum is newly recorded from Brazil based on a collection from Santa Catarina. Inferences from two chloroplast loci, the trnL-trnF region and the rps4 gene, indicate that this sample is closely allied to the primarily North American S. pensylvanicum, but differs by several mutations. Examination of populations of S. pensylvanicum suggests that this species is fairly variable morphologically, and that the Brazilian specimen, although atypic, cannot be distinguished from the Northern Hemisphere populations. The population from Santa Catarina, Brazil, is only the second record of this species from South America and the first from the Southern Hemisphere.