Dorsiventral (bifacial) leaves are commonly horizontal in orientation with distinct upper (adaxial) and lower (abaxial) surfaces. Mesophyll is distinguishable into palisade and spongy tissues with palisade usually restricted to the upper (adaxial) side. Vascular bundles are conjoint and collateral i.e., they possess both xylem and phloem which lie on the same radius. Xylem lies towards the upper (adaxial) side of leaf while phloem lies towards the lower (abaxial) side of leaf. Most of the dicotyledonous leaves are dorsiventral.