The electromicroscopical structure and quinone composition of the osmiophilic, globular, lipiderich plastid inclusions were investigated in several plants. The localisation of the osmiophilic globuli in the plastid stroma and their behaviour toward fixation agents are described. The isolated globuli - here termed plastoglobuli - contain high amounts of lipophilic chloroplasts quinones and apparently no chlorophylls or carotenoids. There exist considerable differences in the relative quinone concentrations of chloroplasts and isolated plastoglobuli. The possible function of plastoglobuli is discussed.