Phylogenic relationship of Gordonia Species (Theaceae) endemic to Sri Lanka

Abstract

A study was carried out to investigate the phylogenetic relationships of Gordonia species (Theaceae) that are endemic to Sri Lanka. During a recent taxonomic rev possible rivision four species of Gordonia, G. ceylanica Wight, G.elliptica Gardner, G.speciosa (Gardn.) Choisy, and G. dassanayakei Wadhwa et Weerasooriya have been identified as naturally occurring in Sri Lanka. All four species are restricted to the upper montane areas of the island. Fresh specimens were collected from all recorded locations, where possible as well as from other likely locations. Ninety three characters that showed variation were identified, studied and coded into different states. Data coding and analysis was done using the computer programs MacClade and PAUP 4.0. The resulting phylogenetic trees were evaluated. The phylogenetic trees supported the monophyly of the genus. The phylogenetic analyses, did not recover the expected monophyletic groups for the four taxa G.speciosa and Gidassanayaket were recovered as two monophyletic clades with support, but the clades were nested either within other large clades or those that contained members of other species. G.el/iptica and Giceylanica are non-monophyletic. The study revealed several confusing character combinations that overlap among the Gordonia species and with the current species limitation for Sri Lankan Gordonia species seems confusing. Further the study unveils the necessity of carrying out a study on species limits of Gordonia with more informative characters.