This occurs mostly on xeric calcareous in midwestern states. In Ky. it is often overlooked but it is largely restricted to clifftops, rocky glades and roadsides with remnants of native grassland. There are also records from Ky. of the generally more eastern taxon, S. ambigua Nutt. (= S. nervosa var. ambigua or S. parvula var. missouriensis (Torr.) Goodman & Lawson). However, ambigua is combined with leonardii in most recent treatments (W), and the plants from Ky. may not be clearly distinct (B, F, M). S. leonardii (including ambigua) reportedly differs from australis and parvula as follows, although keys have varied considerably (F, Y, W): stems minutely puberulent to glabrate, the hairs short, incurved and eglandular (versus short and mixed with longer spreading glandular hairs, at least on angles); leaves mostly 2-11 mm wide (versus 3-14 mm), mostly with 1-2 veins on each side (versus 3-5), the margins revolute (versus flat), minutely puberulent or glabrate below (versus pubescent); calices pubescent with eglandular hairs (versus engludular and glandular). However, intermediate plants may exist; F indicated that these three taxa are just "confluent" varieties.