Typical hirtella is centered in the upper midwest, and occurs mostly on drier ground, often with calcareous soil. It is locally frequent in s. Ill., s. Ind. and s. Ohio (K) but endangered in Ky. The closely related A. longifolia Michx. is sometimes combined, and has been reported from Ky. (BA) but not verified; that taxon is known mostly from wet pine savannas on the Coastal Plain in southeastern states (W). Plants named hirtella on seasonally wet acid soils in PULA (BEREA), with disjunct Gymnopogon brevifolius, which is also typical of wet pine savannas, should be rechecked for possible intergradation with longifolia. The Ozarkian relative, A. stenophylla Gray, has also been reported from Ky. (BA) but apparently in error (M).