In this case, xylem and phloem are present in the same bundle. They combine together in a single bundle. Conjoint vascular bundles are of three types:
- Collateral vascular bundle: Refer to this not on the Collateral vascular bundle
- Bicollateral vascular bundle: In bicollateral vascular bundle, the phloem is present on both the outer and inner sides of the xylem. A strip of cambium is also found on both the outer and inner sides of the xylem. The sequences of vascular tissues are the outer phloem, outer cambium, inner cambium, and inner phloem. These are always open - Bicollateral vascular bundles are found in the members of the Cucurbitaceae family.
- Concentric vascular bundle: In this case, one kind of vascular tissue (xylem and phloem) completely encircles the other from all sides. Concentric vascular bundles are of two types.
- Amphivasal: When phloem lies the center and the xylem completely surrounds the phloem such vascular bundles are called amphivasal. It is found in Dracaena, Yucca , and other monocots and some dicot.
- Amphicribal: When the xylem lies in the center and the phloem completely surrounds the xylem such vascular bundles are called amphicribal. It is found in ferns. Such vascular bundles are always closed.
- Amphivasal: When phloem lies the center and the xylem completely surrounds the phloem such vascular bundles are called amphivasal. It is found in Dracaena, Yucca , and other monocots and some dicot.