Varieties in this southeastern species have proven difficult to maintain (Y). Typical var. diffusa has been considered more southern and perhaps unknown in Ky. (but see Y and W). Plants known as var. interior Fern. & Grisc., including most or all Ky. colls., occur in the lower Mississippi Valley and on nearby uplands. B. diffusa has also been confused with B. asteroides var. recognita, and there may be some hybridization; both taxa are diploids, with 2n = 18 (FNA 20, Y, Townsend 2013). Typical diffusa differs from most asteroides in its more numerous, smaller heads in a more diffuse arrangement with filiform peduncles that have tiny bracts subtending heads (< 10 mm long); its phyllaries are 1.2-1.7 mm long (versus 2.1-2.4 mm); ligules are white (versus pink to white); and pappus awns are 0.23-0.75 mm long (versus 0.8-1.3 mm). The overall growth form of these plants, including varied types of stolon or offset, generally deserves better documentation.