Helianthus petiolaris subsp. petiolaris
Family: Asteraceae
prairie sunflower
[Helianthus couplandii Boivin]
Helianthus petiolaris subsp. petiolaris image
Stems usually hispidulous to strig-illose, rarely ± hirsute to glabrate . Leaves: abaxial faces sparsely, if at all, gland-dotted. Peduncles usually bractless. Phyllaries 3-5 mm wide. Disc corollas: throats abrupt­ly narrowed distal to dense-ly hairy basal bulbs. 2n = 34. Flowering early summer-fall. Dry open areas, usually sandy soils; 10-1500(-2000) m; Alta., Man., Ont., Sask.; Ariz., Ark., Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Kans., La., Maine, Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., S.C., S.Dak., Tenn., Tex., Utah, Va., Wash., W.Va., Wis., Wyo. Subsp. petiolaris is native to western North America and adventive elsewhere (e.g., introduced in Ontario). Hybrids with with H. annuus and H. debilis have been reported.

From Flora of Indiana (1940) by Charles C. Deam
This species probably has just begun to invade the state. It was first reported in 1900. I began to botanize the dune area in 1905 but I did not find it until 1925. It grows in very sandy soil and within the area of its distribution in the state where the sand has been disturbed it has become an abundant weed in cities and along roads and railroads.