Geranium leaf oil gland. Coloured scanning electron micrograph (SEM) of the surface of a leaf of the fragrant Geranium plant, Pelargonium graveolens, showing an oil gland. Green leaf cells are seen, with a leaf pore (stoma) at upper right. On the leaf surface is a spherical structure, a modified glandular hair (trichome), which secretes oils associated with the fragrant odour of this Geranium. The extracted oil of this plant may be used in aromatherapy. Magnification: x670 at 5x7cm size.