Differences in microhabitat and morphology of two sympatric congeneric species Palaquium maliliensis and Palaquium obovatum in the education forest of Hasanuddin University

Two species of Palaquium (P. maliliensis and P. obovatum ) were found coexist in same habitat in the educational forest of Hasanuddin University (Unhas). Two or more species are living in a habitat could be formed from similar parent through genetic isolation process without geographic isolation and was classified as sympatric congeneric species. So far, sympatric congeneric species is still controversial among researchers. Based on this case, the purpose of this study was to determine the microhabitat and morphological differences between the two species. The methods of the study were conducted by purposively selecting 21 samples of P. maliliensis and 20 samples of P. obovatum at the tree level. In each samples found, the microhabitat characteristics (topographic position and slope) and morphological characteristics (leaf, buttress root, and morphological in general) were observed. Morphological measurement data were analyzed with correlation test for intra-species variable and real difference test for inter-species variable. This study concluded that the slope was one of the major microhabitat factors that has driven the process of sympatric speciation between P. maliliensis and P. obovatum. In morphological characteristics, differences between P. maliliensis and P. obovatum appeared in the form of leaves.