Pelecyphora duncanii (Hester) D.Aquino & Dan. Sanchez comb. nov.

Escobesseya duncanii ≡ Escobesseya duncanii Hester, Desert Pl. Life 13: 192. 1941. Escobaria duncanii (Hester) Buxb. Kakteen, Lief. 14, 108c. 1960. Escobaria duncanii (Hester) Backeb., Cactaceae 5: 2966. 1961. Coryphantha duncanii (Hester) L.D.Benson, Cact. Succ. J. (Los Angeles) 41: 189. 1969. Escobaria dasyacantha var. duncanii (Hester) N.P.Taylor, Kakteen And. Sukk. 34: 157. 1983. Neobesseya duncanii (Hester) Lodé, Cact.-Avent. Int. 98(Suppl.): 6. 2013. Type: United States, Texas, Brewster County, in the Edwards limestone of mountains a few mi NW of Terlingua in the Edwards limestone, 3400 ft [1036 m], 1937, F. Duncan s.n. (holotype: DS [271944]).