Orchid petal. Coloured environmental scanning electron micrograph (ESEM) showing papillae (projections) on the petal of the flower of an unidentified orchid. Unlike a conventional scanning electron microscope (SEM), samples put into an environmental SEM do not have to be desiccated or coated in gold, so they appear more natural. Magnification unknown. For the same structures viewed under an SEM see image B765/128.