Helianthus rigidus var. subrhomboideus (Rydberg) Cronquist

Helianthus rigidus var. subrhomboideus (Rydberg) Cronquist is a synonym sensu FNA Ed. Comm., 2006c of:

Helianthus pauciflorus subsp. subrhomboideus (Rydberg) O. Spring & E.E. Schilling, an accepted subspecies name sensu FNA Ed. Comm., 2006c.