Marjoram (Origanum majorana) leaf. Coloured scanning electron micrograph (SEM) of the underside of a leaf from a marjoram plant, showing the numerous hairs (trichomes, spikes) that cover its surface, along with the glandular hairs (yellow), in which the essential oils are stored, which give the leaves their strong aroma. Magnification: x200, when printed 15cm wide.