Vascular tissues are also called complex tissue.

Explanation

In the structure of vascular tissue, structural and functional characteristics of various types of cells are combined. So it is called complex tissue. In xylem tissue, tracheilds, vessels, xylem, parenchyma and xylem sclenenchyma are included.
In phleom tissue sieve cells, sieve tube, companion cells, phleom parenchyma and phleom sclerenchyma (fibres) are included.
Thus it can be said that vascular tissues are comploex tissues.