Proliferation and differentiation processes occurring within the erythroid niche. Early-stage erythroblasts are larger cells with centrally located nuclei; more differentiated erythroblasts are smaller cells containing nuclei located adjacent to plasma membranes. Expelled nuclei undergo phagocytosis by central macrophage. Young multilobulated reticulocytes are initially attached to the macrophage surface and later detach. Illustration by Paulette Dennis.