Axial system All the cells derived from the fusiform initials in the vascular cambium, which are elongated parallel to the long axis of an organ.They compromise the secondary xylem and phloem.

• 轴向系统：在植物次生木质部和次生韧皮部中，源于维管形成层中纺锤状原始细胞的所有的细胞，都沿着器官的长轴平行的伸长。