procambium

Cambium and procambium are their main centers of production.

Primary phloem is laid down by the apical meristem and develops from the procambium.

In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium.

Primary xylem is the xylem that is formed during primary growth from procambium.

Vascular cambium arises from the primary meristem, procambium that remains undifferentiated between the primary xylem and primary phloem.

Although it is composed of non-vascular parenchyma cells, it is still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues it surrounds.