The aim of the present study was to determine support for reducing Chaerophyllum karsianum and C. posofianum, both local endemic to northeast Anatolia, to the synonym C. bulbosum. Chaerophyllum karsianum is closely related to C. bulbosum but distinguished from it by its pink petals, ciliate bracteoles, entire leaf segments, and 12–16 rays according to the protologue and Flora of Turkey and the East Aegean Islands. Chaerophyllum posofianum is also closely related to C. bulbosum but is distinguished from it by its entire leaf segments, ciliate bracteoles, and purple anthers. Flower color of C. bulbosum ranges from white to purple within the same populations or even within the same individuals. The bracteole margin ranges from entire to ciliate in C. bulbosum. Our field observations and examination of herbarium specimens showed that morphological characteristics overlap in all of the examined samples. We also investigated and compared the anatomical and micromorphological characteristics of C. bulbosum, C. karsianum, and C. posofianum fruit. The nucleotide sequence data reported in the present study showed that the internal transcribed spacersequences of C. karsianum and C. posofianum were identical to that of C. bulbosum. Our results strongly support that C. karsianum and C. posofianum be conspecific with C. bulbosum.