As can be seen it is filled to the brim with just stuff. So to start with tissues we have to look at the Vascular Tissues, the Xylem and Phloem. The Xylem brings water to replace losses due to transpiration, and inorganic minerals from the soil. The Phloem transports products of photosynthesis out of the leaf. Then on top the Epidermic Layers we go, the Upper Layer is responsible for preventing water loss from the upper surface even when heated by sunlight. It is able to do this because it is a a continuous layer of cells covered by a thick waxy cuticle. The Lower Layer does the same except it is not hit by sunlight and is generally thinner. Finally there are the Mesophyllic Layers, they are on the inside of the Epidermis Layers, and there are two types. Spongy and the Palisade. The Spongy Layer consists of loosely packed rounded cells with few chloroplasts. This tissue provides the main gas exchange surface so must be near the stomata in the lower epidermis. And the Palisade Layer consists of densely packed cylindrical cells with many chloroplasts. This is the main photosynthetic tissue and is positions near the upper surface where the light intensity is highest.
That's it for stems and leaves today though!