This was reported from Ky. by RAB, but probably in error (MM); no coll. has been located. However, hyssopifolia is close to aspera and they are sometimes combined as varieties. Moreover, these two taxa have similar ranges, with two centers of distribution; hyssopifolium is known mostly from the Atlantic Coastal Plain and the Great Lakes area. It differs from aspera (W) largely in its narrower leaves (mostly 3-6 mm versus 5-15 mm) and lesser pubescence (glabrous to moderate versus hispidulous to strongly pubescent).