A leaf with a vertical orientation would probably not have separate palisade and spongy mesophyll since that arrangement is seen in horizontal leaves in which the spongy mesophyll is near the bottom of the leaf/where carbon dioxide enters the leaf and facilitates movement of gasses through the leaf.
Work Step by Step
Read the material on pp. 764-765 about the normal structure of mesophyll and why it has that structure. You will see that the text description does not apply to a vertical leaf.