Four new species ofCoemansiafrom Taiwan are described. Three produce spirally twisted sporangiophores, and these new taxa increase the number of species in theCoemansia spiraliscomplex from three to six. Each new taxon is morphologically unique.Coemansia biformis, sp. nov., has two different asexual reproductive types on the same thallus; one is straight and the other has a spiral fertile region.Coemansia helicoidea, sp. nov., has stoloniferous sporangiophores with a helicoid fertile region.Coemansia pennisetoides, sp. nov., has a sporangiophore with a fertile region that resembles the inflorescence of the plant genusPennisetum. Coemansia umbellata, sp. nov., has an umbellate sporangiophore branching pattern and a spirally twisted fertile region on the lowest branches. A dichotomous key was provided to identify the 23 acceptedCoemansiaspecies. Phylogenetic analysis based on a combined data set of D1–D2 domains of nuc 28S ribosomal RNA (rDNA) and partial nuc 18S rDNA identifies several independent evolutionary lineages withinCoemansiaand suggests thatSpirodactylon aureumandKickxella alabastrinamay be nested within the genusCoemansia. Sequences of nuc rDNA ITS1-5.8S-ITS2 (internal transcribed spacer [ITS] barcode) are also used to support the description of these new species ofCoemansia. [ABSTRACT FROM AUTHOR]