Sage leaf oil gland. Coloured scanning electron micrograph (SEM) of a freeze-fracture section through a leaf of sage, Salvia officinalis, showing an oil gland. At lower frame are leaf cells. On the leaf surface is a spherical structure, a modified glandular hair (trichome), which secretes oils associated with the odour and essence of sage. The leaves of sage are used for cooking. They also have medicinal properties which reduce fever, cleanse the blood, relieve pain, and are antiseptic. Magnification: x478 at 5x7cm size.