Between the specialized tissues of vascular plants is a lateral meristem known as cambium. It consists of a cylinder of unspecialized meristem cells that gives rise to secondary vascular tissues when it divides and differentiates. By producing secondary xylem and phloem, cambium contributes to the lateral growth of a plant. The trunk of an African cycad is pictured above. It exemplifies the outward growth that the cambium cells trigger by dividing. During this expansion, it pushes the xylem away from the phloem, which is what expands the bark of the plant in a lateral direction.