Premise: Conoclinium coelestinum, the blue mistflower, is a North American species of herbaceous perennial flowering plant in the sunflower family. It was formerly classified in the genus "Eupatorium", but phylogenetic analyses in the late 20th century research indicated that that genus should be split, and the species was reclassified in "Conoclinium".
Hypothesis:  Before the year 2000 Conoclinium coelestinum was in a totally different genus