Bicollateral vascular bundles are present in cucurbits, in which phloem if found on both sides of xylem. The vascular bundle in which phloem is present on the outer side of xylem is called collateral vascular bundle. When xylem and phloem groups are located on different radii the bundles are said to be radial e.g., root. In amphicribral or hedrocentric vascular bundle the phloem encircles xylem.