Phylogeny of the tropical tree family Dipterocarpaceae based on nucleotidesequences of the chloroplast rbcL gene

The Dipterocarpaceae, well-known trees of the Asian rain forests, have been variously assigned to Malvales and Theales. The family, if the Monotoideae of Africa (30 species) and South America and the Pakaraimoideae of South A merica (one species) are included, comprises over 500 species. Despite the high diversity and ecological dominance of the Dipterocarpaceae, phylogenet ic relationships within the family as well as between dipterocarps and othe r angiosperm families remain poorly defined. We conducted parsimony analyse s on rbcL sequences from 35 species to reconstruct the phylogeny of the Dip terocarpaceae. The consensus tree resulting from these analyses shows that the members of Dipterocarpaceae, including Monotes and Pakaraimaea, form a monophyletic group closely related to the family Sarcolaenaceae and ale all ied to Malvales. The present generic and higher taxon circumscriptions of D ipterocarpaceae are mostly in agreement with this molecular phylogeny with the exception of the genus Hopea, which forms a clade with Shorea sections Anthoshorea and Doona. Phylogenetic placement of Dipterocarpus and Dryobala nops remains unresolved. Further studies involving representative taxa from Cistaceae, Elaeocarpaceae, Hopea, Shorea, Dipterocarpus, and Dryobalanops will be necessary for a comprehensive understanding of the phylogeny and ge neric limits of the Dipterocarpaceae.