How is the double perianth different from the simple one?

A flower is a reproductive organ. in which the seeds are formed and therefore its main parts are the stamens and the pistil. For protection from wind, dust and to attract insects, the main organs of the flower are surrounded by a perianth. If the perianth consists of a calyx and a corolla, then it is called double, like an apple tree, a cherry. bell. But if it consists only of a corolla, like a lily of the valley, lily, snowdrop, or only a cup, like a gravilat, then it is called simple. This is their main difference.