Figure 1

The geographic distribution of six closely related Nicotiana species analysed in this study, redrawn from Goodspeed T. H. [ 23 ]. A phylogenetic tree of the six Nicotiana species was constructed from partial nepGS gene sequences obtained from Clarkson et al. 2010 [24], using maximum likelihood method and numbers on each branch represent bootstrap value. Each symbol represents different species. The location of the symbol indicates the distribution of the species that was extracted from Goodspeed T. H [23]. Filled circle: N. obtusifolia; filled triangle: N. linearis; filled square: N. acuminata; plus: N. attenuata; square with cross inside: N. pauciflora; star: N. miersii.