Two African genera of the Gesneriaceae, Saintpaulia and Streptocarpus, are similar in many respects. Both genera have blue to purple flowers, pollen of similar shape and exine sculpting, embryos with one-celled uninucleate chalazal haustoria, shared vegetative structures among some species, and are among the few genera in the Gesneriaceae which include species with chromosome count of n=15. Similarity of these features has indicated that the two genera are likely to be closely related. This study examines the sequences of the chloroplast gene ndhF among several representative Saintpaulia and representatives of Streptocarpus subgenera Streptocarpella and Streptocarpus. The results of this analysis are congruent with those of previous analysis based on the nuclear ribosomal region, ITS. Saintpaulia was found to be nested within Streptocarpus and Streptocarpella. The results raise the possibility of the taxonomic revision of these genera, and this is discussed. Comparisons between the data sets are made regarding utility of the two regions, sample size and outgroup.
Smith, James F.; Kresge, M. E.; Möller, M.; and Cronk, Q. C. B.. (1998). "A Cladistic Analysis of ndhF Sequences from Representative Species of Saintpaulia and Streptocarpus Subgenera and Streptocarpella (Gesneriaceae)". Edinburgh Journal of Botany, 55(1), 1-11. http://dx.doi.org/10.1017/S0960428600004315