Although often recognized in floras, at least as a subspecies (e.g. FNA 20), some studies indicate that this widespread southwestern taxon is not clearly distinct from typical H. subaxillaris (Lam.) Britton & Rusby of the southeastern Coastal Plain (especially ocean dunes); see citations of Y and W. In Ky., most records are from dune-like sandy areas along the lower Ohio Rv. and the Mississippi Rv., or nearby; it does not generally appear to be an alien weed as sometimes stated (W). However, the coll. from JEFF (KY) was a waif found in the parking lot by the herbarium in 1996.