The genus Symphyotrichum (Asteraceae) contains species that are found throughout North America. Over forty-seven species occur in Missouri (Steyermark et al., 2006). Symphyotrichum pilosum is among the most widespread and weediest of our native asters while S. parviceps is less common and mainly occurs as scattered populations in the eastern half of the state. The purpose of this study is to identify an unknown Symphyotrichum species found in a glade near Steelville, MO. It has been argued that the aster is a hexaploid variant of S. parviceps, another cytotype of S. pilosum or a new unknown species. However, the base chromosome number for Symphyotrichum is nine and has been reduced to eight. The unique Aster’s chromosome counts have revealed that the aster is a dodecaploid (2n=96=12X). This number is larger than all known chromosome numbers for S. pilosum (n=16, 20,24) and S. parviceps (n= 16,24,32) in the state of Missouri. Internal Transcribed Spacer sequence data was not able to resolve relationships among these taxa. Microsatellite markers are currently being developed to determine the relationships among these taxa.