Which are the four famous coffee beans?

The editor of the four famous beans said that the origin of coffee plant can be traced back to millions of years ago, in fact, the real time when it was discovered can no longer be tested. According to legend, Coffee is a shepherd named Kaldi in the highlands of Ethiopia. When he discovered that his sheep had inadvertently eaten the fruit of a plant, he became very lively and full of vitality, and discovered coffee ever since. All