Section of a leaf: chlorophyll containing outgrowth of a stem or branch; the site of photosynthesis.
Cuticle: thin superficial skin of a leaf.
Upper epidermis: outer layer of the leaf.
Spongy mesophyll: set of cells forming the central layer of a leaf.
Guard cell: part of the stoma.
Lower epidermis: lower layer of the leaf.
Stoma: organ of the leaf that allows the exchange of gases.
Air channel: place in which air circulates.
Phloem: conductive tissue that carries sap and other liquids.
Xylem: plant tissue of which wood is formed.
Vein: line outlining a leaf division.
Vertical palisade cell: set of cells forming the upper and lower layers of a leaf.