Stiff sunflower, hélianthe rigide

Helianthus laetiflorus Persoon var. rigidus (Cassini) Fernald; H. rigidus (Cassini) Desfontaines

Plants 80–200 cm. Leaves usually alternate distally; blades oblong-lanceolate to lance-ovate, 8–27 cm, apices acuminate.

Flowering late summer–fall. Dry to moderately wet prairies, open places; 50–600+ m; Alta., B.C., Man., Ont., P.E.I., Que., Sask.; Ark., Conn., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Mass., Mich., Minn., Mo., Mont., Nebr., N.H., N.J., N.Dak., Okla., R.I., S.Dak., Tex., Vt., Va., Wis.

Subspecies pauciflorus is introduced in Ontario, and probably in all eastern Canada.