Treatment remains tentative, but this segregate of humilis appears generally distinct in Ky. and the mapping here is accurate. The type appears to be from FAYE (Garman & Rose at GH). R. humilis, in its broader sense, ranges widely across east-central states on dry soils of diverse types, but usually calcareous in Ky. Variation needs further study; F recognized six intraspecific taxa; see also St for a divisive treatment. Most plants of this complex in Ky. lack dense long hairs, and, using older treatments (Fernald 1945; F, St, Cr), they would be referable to var. calvescens Fern. or perhaps the infrequent "var. humilis f. grisea Fern." (a possible intermediate with dense hairs but not long or spreading). Var. calvescens was recorded by F from calcareous soils of the Interior Low Plateaus (especially the Nashville Basin) and around the Appalachians. It is a locally abundant taxon in xeric or subxeric rocky glades and grassland, prospering sometimes where trampled or mowed. There has been much confusion with humilis in its strcter sense; see notes under that name. Fernald (1945) indicated that calvescens differs as follows: younger internodes glabrous, glabrescent or with only few scattered hairs on angles (versus copiously villous-hirsute to canescent-pilose or -puberulent); leaves glabrous, glabescent or with only sparsely short-hirsute on nerves beneath and margin (versus usually villous-hirsute on veins and margins), narrowly elliptic-oblong to oblong-lanceolate (versus elliptic-oblong to oval), the larger ones 2-6 x 1-3 cm (versus 3-8 x 1-4 cm); corolla 2-3.5 cm long (versus3-8 cm), the tube 0.7-2.3 cm (versus 1.2-5 cm). Also, one of the most distinctive characters is overall habit: usually 10-30 cm high (versus 30-70 cm), with stems sprawling, not erect (versus with at least some erect stems).