This is widespread on more base-rich soils from Central America to southeastern states, and can be expected on the Coastal Plain in w. Ky. The species has been recently determined in several counties of w. and c. Tenn. (M. Brock, pers. comm.), but it has not been previously recognized in that state (Ch). M. Brock (pers. comm. ) has recently placed provisional identifications as tenuispatheus on two colls. from Ky. at APSC: M. Medley #15555 from MCRA (Airport Prairie); and R. Hannan #KEP01-00994 from MUHL (Cypress Creek). It is likely that a thorough review of colls. from Ky. and adjacent states will expand the known range of this species in the central Mississippi and lower Ohio Valleys. Much "glomeratus" previously reported from the West and East Gulf Coastal Plains appears to be this species (Campbell & Seymour 2018). But colls. of "Dr. Peck" sent in 1840 to C.W. Short in Ky. (NY) from La. have been misattributed to Ky. in SERNEC (Feb 2020). Compared to glomeratus sensu stricto (W), tenuispatheus usually has distinctly narrower raceme sheaths (mostly 2-2.5 mm versus 2.4-3.4 mm), shorter ligules (averaging 0.8 mm versus 1.2 mm) with longer cilia (0.2-0.9 mm versus 0-0.3 mm), and more scabrous glumes; culm sheaths often lack scabrosity (versus consistently so). But the species can also be easily confused with virginicus and other allied species; see W for detailed key.