The origin of Datura metel (Solanaceae): genetic and phylogenetic evidence

Using the analysis of nine isozyme systems and cladistic analysis of 32 morphological characters of the Mexican species of the section Dutra of the genus Datura, evidence was sought on the origin of the cultivated D. metel L. The genetic similarity and the phylogenetic relationship suggest that D. metel is related more closely to D. inoxia Mill. than to the other taxa of the section Dutra based upon the small genetic distance between them. The cladistic analysis revealed two main clades: the long-lived, tuberous rooted perennials (D. inoxia, D. lanosa A.S. Barclay ex Bye, D. metel, and D. wrightii Regel) and the tap-rooted annuals (D. discolor Bernh., D. kymatocarpa A.S. Barclay, D. leichhardtii F.V. Muell. ex Benth. ssp. pruinosa (Greenm.) Barclay ex Hammer (syn.: D. pruinosa Greenm.), D. reburra A.S. Barclay). Datura inoxia is the sister taxon of D. metel next to which is D. wrightii while D. lanosa is the basal taxon of this group. The combination of genetic and cladistic data indicates that D. inoxia is most likely the progenitor of D. metel.