Clarence Fred Anderson was the son of John W. Anderson and Janie Key.
John Anderson was the youngest son of Jonathan and Sarah Cummings Anderson. One of their other sons, James Cummings Anderson, is my 2nd ggf.
Jane Key is the daughter of Lewis Clark Key. Lewis's sister, Dorcas, married James Cummings Anderson. This would make Dorcas and Janie aunt and niece, respectively (and sister's-in-law).