Polyphyletic Trachyspermum (Umbelliferae) revisited: a contribution of molecular and carpological data

Abstract

Trachyspermum is an economically important genus widely distributed in the Old World. A modern monographic survey is absent, so the number of species and their affinities are treated in the regional Floras extremely contradictorily. In this study, all species names available in the genus Trachyspermum were revised, and 19 validly published names are kept in the genus. To investigate the species relationships in Trachyspermum, which was shown in previous studies to be polyphyletic, nrDNA ITS sequence data were determined for additional taxa, accompanied with study of fruit morphology, micromorphology and anatomy. Our molecular analysis indicates that Trachyspermum is an aggregate of at least seven distant lineages, and that T. ammi (generitype) does not group with other Trachyspermum species. Many carpological characters do not agree with these groups, being rather homoplastic, but we identify that types of hairs in fruit indumentum and microsculpture of hair cuticle are consistent with molecular clades within Trachyspermum. Our investigation provides one more step towards to the taxonomic revision of the genus, and the possibility of splitting of the current Trachyspermum into monophyletic genera is discussed.