The original Tragopogons were from 2 areas in Europe which never came into contact with eachother. This contact only happened in the Palouse region after immigrants brought them with them to the area, they then then interbred with the other species to produce
allopolyploid hybrid offspring. These tetraploid offsping have characteristics that are better suited to the environment here and also produced fertile seeds that continued the line.
A common mistake that is made when discussing these plants is that they mutated from the parent lines...they did not. Rather, the diploid parents gave rise to the tetraploid lines using the existing genetic information. This is an example of sexual reproduction mixing genes in novel combinations.
T. mirus for example has purple flowers unlike either of the parents and this is perhaps the most striking difference that can be observed in this new species and the parent lineages.
Poloyploidy is one way that plants can produce new species while animals seem unable to produce fertile offspring in this manner. Another commonly seen plant that has appeared recently is the
Triticum aestivum which is also a polyploid species.