A new species of (Entylomatales, Exobasidiomycetes) on the ornamental plant expands the species complex.

The plant genus (Apiaceae) includes various species used as condiments, ornamentals in gardens, or as elements in floral arrangements. In recent years, there has been a surge in interceptions from South America at U.S. ports of entry, leading to the subsequent destruction of these plants due to the presence of an unidentified species of (Entylomatales, Exobasidiomycetes). The combination of morphology, host, and geographic origin did not align with any reported species on . This study aimed to identify and characterize this unknown sp. ascertain its phylogenetic relationship with other species, and verify the identity of the host plant. Morphological and phylogenetic (nuc rDNA internal transcribed spacer [ITS] regions) analyses were performed, in context with available sequences and species of . Nuc rDNA ITS was also used to attempt the identification of the host. Findings reveal that the unidentified sp. forms a distinct and well-supported clade separate from other species on . Its closest relatives include , and . Morphologically, it resembles , and ; however, a combination of host affiliation, geography, and morphology distinguishes the new sp. from these five species. Therefore, the new species is described herein. The host plant was confirmed as . This research increases knowledge of diversity and contributes to understanding the dynamics of pathogen movement and potential invasion into new territories.