This occurs in east-central states, mostly from the central Mississippi Valley to the Great Lakes region. Although known previously as just a variety or form of tenuis, these plants have been recently promoted to species status by R.E. Brooks (FNA 22). Differences in ecology are not clear; anthelatus may be concentrated on more open sites with more seasonal wetness (see also Y; W. Knapp, pers. comm.). Closer study of material filed under tenuis is desirable to check on taxonomy and distribution. J. anthelatus differs in having capsules widely spaced along the usually diffuse branches of the inflorescence (versus congested along internodes about as long as perianth), and usually < 3/4 length of perianth (versus 3/4 or more). Also plants are generally 7-9 dm tall (versus < 7 dm).