Carnivorous plant leaf scales. Coloured scanning electron micrograph (SEM) of leaf scales from the yellow pitcher plant (Sarracenia flava). These are found on the inside surface of the leaves used by this carnivorous plant to trap insects. The scales point downwards, and secrete a waxy substance that causes insects to lose their footing and fall into the trap. They are attracted by a sweet-smelling liquid secreted by glands (one at lower centre). Larger, spiny scales (not seen) stop large insects from climbing out of the trap. The trapped insects are digested by enzymes, providing the plant with nutrients not found where it grows. Magnification: x1670 when printed 10cm high.