Northern Prairie Wildlife Research Center
A plant of statewide distribution, stiff sunflower is native from Ontario to Georgia and westward nearly across the continent, at elevations up to 8,000 ft. The species has spread adventitiously with human disturbance to Quebec and Virginia.
Stiff sunflower is perennial by long rhizomes and often forms patches on the prairie. Plants may be five feet tall, but one to two foot specimens are most frequently encountered. Rough, hairy leaves grow in pairs up to about the middle of the stiff, prickly stem. Flower heads are purplish-brown in the center, with yellow rays about an inch long. From one to five flower heads are found on each stem. Fruits are typical sunflower achenes about 3/16-inch long.
Moderately and lightly grazed prairie supports the highest populations of stiff sunflower. This indicates the plant will be consumed by livestock. Many of the 60 or so species sunflower are used for foods, medicines, and industrial products, but stiff sunflower has no known economic value other than forage.
Stiff sunflower is, of course, a member of the sunflower family (Asteraceae). Aster means "star" in Greek, in reference to the radiate arrangement of flowers in the heads. The sunflower family is by far the largest in North Dakota and in most temperate areas of the Northern Hemisphere. The generic name Helianthus stems from the Greek helios, "the sun," and anthos, "a flower." The specific epithet rigidus means "rigid" in botanical Latin. Stiff sunflower was first described for science by the eminent French authority on the Asteraceae Alexandre Cassini (1781-1832).