Robust, mostly 1-2 m; lvs 9-15 pairs below the infl, oblong-lanceolate to lance-ovate, acuminate, 8-27 cm; chiefly midwestern, in Mich., Wis., e. Minn., Io., e. Neb., e. Kans., Mo., and Okla., and intr. eastward. (H. rigidus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.