To test the hypotheses that Oreomyrrhis species form the sister clade of North American Chaerophyllum and thus render the mainly Eurasian Chaerophyllum paraphyletic, two chloroplast intergenic spacers (atpB-rbcL and trnS-trnG) were analyzed. Phylogenetic estimates using maximum parsimony, maximum likelihood, and Bayesian inference of separate and combined matrices strongly support the monophyly of Oreomyrrhis and its sister-group relationship with North American Chaerophyllum. Chaerophyllum temulum, the type species of Chaerophyllum, is the sister taxon to the clade composed of Oreomyrrhis and North American Chaerophyllum. Relationships among other major clades of Chaerophyllum are congruent with previous studies. Based on these phylogenetic estimates, all currently recognized taxa of Oreomyrrhis are synonymised with Chaerophyllum. The unranked names, North American clade and Oreomyrrhis clade, are advocated to designate the two well-supported clades within Chaerophyllum sect. Chaerophyllum. The proposed nomenclatural changes include three new names, Chaerophyllum australianum, Chaerophyllum guatemalense, and Chaerophyllum novae-zelandiae, and 26 new combinations, Chaerophyllum andicola, Chaerophyllum argentum, Chaerophyllum azorellaceum, Chaerophyllum basicola, Chaerophyllum borneense, Chaerophyllum brevipes, Chaerophyllum buwaldianum, Chaerophyllum colensoi, Chaerophyllum colensoi var. delicatulum, Chaerophyllum colensoi var. hispidum, Chaerophyllum colensoi var. multifidum, Chaerophyllum daucoides, Chaerophyllum eriopodum, Chaerophyllum gunnii, Chaerophyllum involucratum, Chaerophyllum lineare, Chaerophyllum nanhuense, Chaerophyllum orizabae, Chaerophyllum papuanum, Chaerophyllum plicatum, Chaerophyllum pulvinificum, Chaerophyllum pumilum, Chaerophyllum ramosum, Chaerophyllum sessiliflorum, Chaerophyllum taiwanianum, and Chaerophyllum tolucanum.