By Harold McGee
Ground tissue is the primary mass of cells. Its purpose depends on its location in the plant. In leaves the ground tissue performs photosynthesis; elsewhere it stores nutrients and water. Cells in the ground tissue usually have thin cell walls, so the tissue is generally tender. Most of our fruits and vegetables are mainly ground tissue.
Vascular tissue runs through the ground tissue, and resembles our veins and arteries. It is the system of microscopic tubes that transport nutrients throughout the plant. The work is divided between two subsystems: xylem, which takes water and minerals from the roots to the rest of the plant, and phloem, which conducts sugars down from the leaves. Vascular tissue usually provides mechanical support as well, and is often tough and fibrous compared to the surrounding tissue.