Delimitation of Genera in Apiaceae with Examples from Scandiceae Subtribe Scandicinae

Of the 455 known genera in Apiaceae (Umbelliferae), 41% are monotypic and 26% comprise only two or three species each. Similarly, of the 16 genera constituting Scandiceae Spreng. subtribe Scandicinae Tausch, seven (Balansaea Boiss. & Reut., Kozlovia Lipsky, Krasnovia Schischk., Myrrhis Mill., Myrrhoides Fabr., Sphallerocarpus DC. and Todaroa Parl.) are monotypic, and two (Neoconopodium Pimenov & Kljuykov and Tinguarra Parl.) are bitypic. Phylogenetic analysis of the subtribe, using molecular (rDNA ITS), morphological and anatomical data, indicates that the number of genera may be reduced with only three, Todaroa, Sphallerocarpus and Myrrhis, retained as monotypic. Remaining taxa form eight clades that are supported by high bootstrap values and are morphologically distinct. Four of these clades (Anthriscus Pers., Geocaryum Coss., Osmorhiza Raf. and Scandix L.) are equivalent to currently recognized genera. Kozlovia, Krasnovia and Neoconopodium form a well[hyphen]supported clade that may be recognized as the single genus Kozlovia, and Myrrhoides is grouped with Chaerophyllum L. Tinguarra and Athamanta L. form a monophyletic group that is well supported by analyses of morphology, fruit anatomy, and combined morphological, anatomical and ITS sequence data; however, this group is not maintained in separate analyses of ITS sequences. Similarly, the group formed by Conopodium W. D. J. Koch and Balansaea is monophyletic in morphological, anatomical, and combined analyses, but is not supported by the separate analyses of ITS sequence data. All of these groups are well delimited on the basis of fruit characters that have long been regarded as essential in umbellifer taxonomy. One new combination is proposed: Athamanta montana (Webb ex H. Christ.) Spalik, A. Wojew. & S. R. Downie.