20a. ssp. glabrata (E.L. Braun) S.B. Heard & Semple

S. rigida var. glabrata E.L. Braun

Oligoneuron rigidum var. glabratum (E.L. Braun) G.L. Nesom

Stems 40–120 cm long, glabrous or sparsely hairy below the midpoint (often more densely hairy toward the tip). Involucral bracts all glabrous on the outer surface (hairy along the margins), those of the inner series relatively broad and rounded to bluntly pointed at the tip. 2n=18. September–October.

Uncommon, known thus far from a single historical collection from Jefferson County (southeastern U.S. west to Missouri and Texas). Dolomite glades.

This subspecies tends to have slightly thinner, more lax leaves than the others. The report of ssp. glabrata from Ozark County by Turner and Yatskievych (1992) was based on a misdetermined specimen of ssp. rigida.