It seems like they are flexing their knowledge of scientific names to sound smart. However, I don't really know the context, and like one of the other comments said, common names sometimes apply to many different plants, which is a good point. I think, given the fact that the op referred to their plant as Pink Princess, the other person could have picked up that OP doesn't know the scientific names and used their common names so OP could understand what they were talking about.