A cambium (PO:0005597) that is located between and gives rise to secondary xylem (PO:0005848) and secondary phloem (PO:0005043). [source: ISBN:047125208]
Comment
A vascular cambium produces cells in both directions, centrifugally and centrifically, leading to an increase in the cross-sectional area of a plant axis (PO:0025004).