Abstract:We investigated the pollen morphology of 50 individuals(from five populations) of a suspicious species(in sect. Ranunculoides Chen et C.M.Hu), distributing at northwestward in Zhejiang Province. The pollen morphology of this suspicious species were high diversity. Based on the shape and number of aperture and their component, five pollen types could be recognized, including stephanocolpate type, colpi more than pores type, pores more than colpi type, pantoporate type and ringcolpate type. The component of pollen types was comparatively different among studied populations. There might be more than one pollen types within the same individual or the same anther. There might be high variability of pollen morphology at intraspecific level. Pollen morphology characters showed this suspicious species was a distinct and authentic new species, and likely evolved from cross bred progeny of parents with stephanocolpate type and pantoporate type pollens.