LINDQVIST, CHARLOTTE* and VICTOR A. ALBERT. Biodiversity and Systematics, Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487-0345. - A high elevation ancestry for the Usambara Mountains and lowland populations of African violets (Saintpaulia, Gesneriaceae).
As a follow-up to previous research, we present a cladistic analysis
of 5S nuclear ribosomal DNA non-transcribed spacer (5S-NTS) sequences
representing 55 Saintpaulia accessions and one
Streptocarpus outgroup taxon. All formally described and
potential Saintpaulia taxa are included except for S.
'mafiensis' and the possibly extinct S. inconspicua. Most
notably, Saintpaulia shumensis, the highest elevation species
in the Usambara Mountains, is resolved, albeit with marginal parsimony
jackknife support, as the sister taxon to all remaining members of the
Usambaras/lowland clade, which is otherwise poorly structured. It is
hypothesized that Saintpaulia shumensis may show a relictual
distribution in the Usambaras, as there appears to be a phylogenetic
trend from higher to lower elevation among the major clades of
Saintpaulia. Further issues discussed include the implications
of intra-individual nucleotide polymorphism and the narrow genetic
basis for drastic differences in trichome morphology, a cardinal
characteristic for Saintpaulia taxonomy.
Key words: Eastern Arc Mountains, elevation, molecular systematics, Saintpaulia shumensis, trichomes, Usambara Mountains