This is widespread in seasonally wet grasslands across temperate North America, mostly on base-rich soils of midwestern regions, but it is much less frequent in Atlantic states. Plants vary much in overall robustness and number of heads per inflorescence. However, no taxonomic variants have been recognized in floras. The more slender northern species, J. nodosus L., is closely related to torreyi and should be expected. It is known from within 100 miles of the state line in Ill., Ind., Ohio and W.Va. (K, PL). Both species produce slender tuberiferous rhizomes.