This distinct segregate of altissima is known mostly from the Great Plains (Semple et al. 2015). It has smaller involucres (ca. 2-3 mm long versus 3-4 mm), and includes some diploids (as well as tetraploids and mostly hexaploids), appearing somewhat transitional to canadensis (FNA 20); indeed, Ladd & Thomas (2015) indicate that it appears closer to canadensis in Mo. The plants mapped here appear somewhat distinct, with a clustering of records in northern regions of the state, but further verification is needed.