In asexual cultures, a colony of Pleodorina usually consists of 32, 64, or 128 cells. It is not a mere mass of the same kind of cells but is an organized structure composed of two types of differentiated cells, i.e. reproducing cells and somatic cells. When isolated from mother colony, reproducing cells ceased to grow and began to divide to make up small colonies consisting of 2, 4 or 8 cells size of the colonies varying according to the initial state of the reproducing cells. In these small colonies, reproducing and somatic cells were clearly distinguishable.