False-colour scanning electron micrograph (SEM) of the surface of a rose petal, Rosa sp.. The petals of most flowers are in fact stamens which have switched roles during evolution from sexual organ to advertising agent. Although they appear smooth to the eye, they often revealed fine sculptured texture under the microscope. This rose petal consists of closely packed cells, each topped with fine ridges. The reason for this is unknown, but may be related to the reflection of light from the petal. Magnification: x60 at 35mm size. Reference: MICROCOSMOS, figure 4.26, page 80.