E. lancifolium

E. semiserratum

E. linearifolium

E. lancifolium

E. semiserratum

E. linearifolium

E. semiserratum

E. serotinum

Eupatorium semiserratum complex – 3 morphologically similar species each share a 1 bp deletion in ITS-1 vs. all other Eupatorium (see dotted red arrow in upper right, compared to E. serotinum); and the 3 species each have unique indel features:  a 3 bp deletion in ITS-1 characterizes E. linearifolium (below, black lines/arrow); a 3 bp insertion in ITS-2 characterizes E. semiserratum (lower right; black lines/arrow; dot highlights an additional single bp difference).