Memes

Oh that's Seminole. Which most racist people are too ignorant to realize meant runway slave (In this context, the majority of Seminole were/are straight up indigenous), and thus actually a black ancestor they didn't want to acknowledge. But they had to put something on the family tree in the family bible. That's a fun one to find in the South East US.

Cherokee is usually a straight up fiction. Personally I think the idea got popularized because people like feeling special and native Americans were big news in the 1970's. Racists also jumped on it as a means of showing native Americans didn't deserve special rules or treatment.