Leaf veins. Light micrograph of veins in a Prunus sp. (cherry tree genus) leaf. The vein comes from top right before successively dividing up into smaller vessels. The veins in a leaf transport food (carbohydrates) andwater in and out of the leaf. The branching seen here is characteristic of flowering dicotyledonous plants. Monocotyledons have narrower, parallel veins. Magnification:- X17 at 5x7cm size.