This is a widespread North American species that usually grows on fertile soils in woodland with moderate stress or disturbance (see also: FNA 24). A few colls. (e.g. from GRAV at WKY) may be transitional to typical obtusata, but intermedia is generally quite distinct. There has been much confusion among the species of Sphenopholis in Ky., and a more detailed key is still needed (e.g. based on F); 2n = 14 in all three cases. According to FNA 24, the name S. pallens (Biehler) Scribn. is applicable to supposed hybrids of pensylvanica and obtusata (or perhaps intermedia). However, records of pallens from Ky. (Anderson 1924, RAB) are probably all referable to intermedia (M).