Systematic studies in South East Asian Malvaceae, subfamily Sterculioideae

A parsimony analysis of ndhF nucleotide sequences representing 24 species and 13 genera of Sterculioideae strongly support its monophyly. Within Sterculioideae four major clades are recognised but relationships among them are not resolved. This analysis suggests the recognition of Argyrodendron as separate from Heritiera, Acropogon as separate from Sterculia, and Tarrietia as part of Heritiera. Current circumscriptions of Hildegardia and Firmiana are not supported. The use of floral characters in delimitation of genera may be more appropriate than the traditional use of fruit characters. 20 new ITS, 17 new trnL-trnF, 15 new trnH-psbA, and 13 new trnS-trnG sequences were obtained for species of Scaphium, Pterocymbium and outgroups from Sterculioideae. Phylogenetic reconstructions using parsimony and Bayesian inference were undertaken for each region, chloroplast regions combined, and ITS and chloroplast regions combined. For each region parsimony and Bayesian analyses generally produced congruent topologies, but results from nuclear and chloroplast data differed, albeit with weak support. The chloroplast data indicated Scaphium to be monophyletic whereas the ITS tree placed Pterocymbium within Scaphium, rendering it paraphyletic. Within Scaphium some support is given to a Sc. Longipetiolatum – Sc. Scaphigerum clade, resolved as sister group to other Scaphium species, for the recognition of Sc. Macropodum and Sc. Affine as separate species, the recognition of Sc. Longiflorum as separate from Sc. Affine, and to Sc. Linearicarpum as sister to a clade composed of Sc. Macropodum, Sc affine and Sc. Longiflorum. A revision of Scaphium recognizes eight species, of which one is newly described. Six species names are placed in synonymy or are excluded from Scaphium. An account of Sterculiaceae s.1. for the Tree Flora of Sabah and Sarawak covers 11 genera, 47 species and five varieties.EThOS - Electronic Theses Online ServiceGBUnited Kingdo