A vascular bundle is a long continuous strand of conductive tissues that extend from the roots through the stem and into the leaves. It consists of xylem and phloem that may differ in their arrangement. A vascular bundle having the phloem and cambium strands on both the outer and inner sides of xylem are called bicollateral. The arrangement is in a sequence of outer phloem, outer cambium, xylem, inner cambium, and inner phloem, for example, Cucurbita.