This rhizomatous species is widespread on damp fertile soils in much of eastern North America. However, it is centered in midwestern regions, probably often overlooked in Ind. and Ohio, and rare to absent in more southeastern states (K, W). Typical plants are tetraploid (2n = 32) and appear somewhat intermediate between lateriflorum and lanceolatum in several characters, but they are distinguished by uniformly puberulent upper leaves and stems (FNA 20, Y and their citations). Disc corollas of ontarione have lobes about 1/2 as long as their inflated sections; those of lateriflorum are about 2/3; those of lanceolatum and other related species are about 1/3 or less. Ray laminae are mostly 3.5-5.5 mm long, about the same size as those of lateriflorum but averaging smaller than thoe of lanceolatum (which are often up to 10 mm).Typical habitat of ontarione is also intermediate, between wetter and drier or poorer soils. S. ontarione seems consistently distinct in Ky., but it is sometimes confused with lanceolatum since lower leaves are usually glabrous except for midribs (versus completely glabrous in most lanceolatum of Ky.). Less hairy diploids around the Great Lakes have been named var. glabratum (Semple) Brouillet & Bouchard (= A. laterifllorus var. tenuipes; J.C. Semple, pers. comm.).