Symphyotrichum ascendens x

Symphyotrichum ascendens is the only species in the tribe Astereae with a derived chromosome base number of x2=13 (8+5); its morphology is intermediate between the two putative parents: S. spathulatum and S. falcatum.

It is native to the western United States with 2n=26 plants in the western portion of the range and 2n=52 plants further east.