A bicollateral vascular bundle is characterised by

1. Phloem being sandwiched between xylem
2. Transverse splitting of vascular bundle
3. Longitudinal splitting of vascular bundle
4. Xylem being sandwiched between phloem

Bicollateral vascular bundles have phloem in both outer and inner side of xylem. These type of bundles occur in cucurbitaceae.