Phylogenetic relationships in the genus Lichtensteinia (Apiaceae) based on morphological, anatomical and DNA sequence data

Evolutionary relationships within the poorly known and anomalous South African endemic genus Lichtensteinia were elucidated. Phylogenetic analysis of morphological and anatomical characters suggests that there are two main groups of species, viz. the L. obscura-L. globosa-L. interrupta (including L. kolbeana) clade and the L. latifolia-L. trifida-L. lacera-L. crassijuga clade. Furthermore, Lichtensteinia is not monophyletic, with the former group allied weakly with the Namibian endemic genus Marlothiella and the latter group allied strongly with Annesorhiza macrocarpa. In contrast, the results of phylogenetic analyses of nrDNA ITS and cpDNA trnQ-5'trnK sequences, separately and combined, as well as the results of a total evidence analysis of all available data, suggest three main groups of species in a monophyletic Lichtensteinia: the aforementioned L. latifolia-L. trifida-L. lacera-L. crassijuga complex, a clade comprising L. interrupta and L. globosa, and L. obscura. DNA sequence data, however, are not currently available for Marlothiella. The new species L. globosa B.-E. Van Wyk and P.M. Tilney is sister group to L. interrupta in the molecular analyses; in the analysis of morphological/anatomical data, however, the relationships among L. globosa, L. interrupta and L. obscura are equivocal. Lichtensteinia lacera and L. trifida are each not monophyletic based on the molecular phylogenies. The various populations of L. lacera and L. trifida examined are morphologically quite distinct, with large differences observed among populations but limited variation within populations. The size and shape of the leaves and of the marginal teeth, as well as the presence and length of setae, were found to be of diagnostic value in distinguishing among the species.