The three lineages in the bone marrow are generally referred to as: first, the granulopoietic lineage, which is divided into the primitive granulocytes, the early granulocytes, the middle granulocytes (which in turn include the three types of acidophilic, basophilic and neutrophilic middle granulocytes), the late granulocytes, and those of the three types of mature rod-shaped nucleated granulocytes. The second is the erythroid lineage. The third is the megakaryotic lineage, which is subdivided into many more. The bone marrow trilogy is not the same as the blood trilogy, which generally refers to white blood cells, red blood cells, and platelets, and is usually used if a bone marrow aspiration is performed.