In Indonesia harendong are more commonly known as Melastoma, the most widely known species is M. malabathricum and M. affine. Several studies using harendong as subject sometimes categorizes M. malabathricum and M. affine as two different types, but in other studies both referred to as a synonym. Until recently, no study has discussed harendong plant taxonomy based on morphological or cytogenetics. In an effort to make harendong as phytoremediation agents, taxonomy problem becomes very important, because the physiology and metabolism of each different type of plant will be different. This research aims to study the morphological variation and cytogenetic of three harendong plant samples from some places in West Java; to study the gene expression due to heavy metal treatment, and to investigate the toxic effect of heavy metals on the growth of M. malabathricum. The study was conducted on the morphological analysis of flowers and leaves. Cytogenetic analysis was performed by counting the number of chromosomes from root samples using squash with aceto-carmin staining techniques. In order to carry out a preliminary study on the potential of this plant as a phytoremediation agent, M. malabathricum L. were grown hydroponically in a nutrient solution with different concentrations of lead (Pb), cadmium (Cd), and copper (Cu). The plant's ability to accumulate those heavy metals in root, stem and leaves were also determined. The results indicate that the investigated heavy metals were absorbed from the soil solution and then accumulated in the tissues of Melastoma plants in varied concentrations. The highest accumulation were lead (Pb) and cadmium (Cd), and copper (Cu) while the amount of absorption rate and accumulation were: Pb > Cd > Cu, respectively.