In a dorsiventral dicot leaf, the outer epidermis is followed by a layer of mesophyll layer. The mesophyll is made up of two types of paranechyma cells- palisade parenchyma and spongy parenchyma. Palisade parenchyma is cylindrical in shape and are compactly packed whereas spongy parenchyma is loosely packed.
In the bundle sheath of the dicot leaf, the xylem is usually arranged on top, hence adaxial and phloem at the bottom, so referred to as abaxial.