focus on... Phylogeny of the genus Peperomia
A molecular phylogeny of this giant genus based on a representative
sampling has been published in Plant Biology 8 (2006): 93-102.
The genus Peperomia is one of the largest genera of basal angiosperms comprising about 1500-1700 pantropically distributed species. The currently accepted infrageneric classification (Dahlstedt 1900) divides Peperomia into nine subgenera and seven sections. This classification is based on some 200 species, primarily using fruit morphology. The present molecular study of 48 species representing 8 out of 9 subgenera sensu Dahlstedt (1900). This work is based on the matK gene and surrounding trnK intron from the chloroplast genome and supports only very few clades of the classification of Dahlstedt (1900). This paper provides the first molecular phylogeny for the genus Peperomia and therewith another source for hypothesis of the natural evolution of this genus.
Monophyletic clades within Peperomia are identified and previously used morphological characters to circumscribe groups are critically reviewed. This first phylogenetic study with a representative sampling of the genus shows that most of the infrageneric taxa sensu Dahlstedt (1900) are poly- or paraphyletic (which means that the members of one group are scattered throughout other groups or that within one group another group is found) and suggests several new groupings. Parallel character evolution is also hypothesised, which has mislead previous authors with regard to the description of infrageneric taxa. Indeed, most of the subgenera sensu Dahlstedt seem to be paraphyletic as their circumscription was based on morphological characters which are subject to parallel evolution. Based on chloroplast matK/trnK, only two subgenera from Dahlstedt (1900), Micropiper and Sphaerocarpidium (including Erasmia) and the three sections of subgenus Rhyncophorum are monophyletic.
[Stefan Wanke & Marie-Stéphanie Samain]
This paper results from an intensive cooperation between Ghent University and Dresden University on the giant genus Peperomia.
Ref.: Wanke S., Samain MS., Vanderschaeve L., Mathieu G., Goetghebeur P., Neinhuis C.
(2006). Phylogeny of the genus Peperomia (Piperaceae) inferred from the trnK/matK region (cpDNA). Plant Biology 8: 93-102.