This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Perennial herbs (a tropical species annual), with opposite petioled 3-ribbed leaves, and large peduncled terminal and axillary heads of tubular and radiate yellow flowers. Involucre hemispheric or broadly campanulate, its bracts oblong or lanceolate, imbricated in 2 or 3 series. Receptacle convex or conic, chaffy, the chaff enveloping the disk-flowers. Ray-flowers pistillate, fertile, the rays spreading, the tube very short, commonly persistent on the achene. Disk-flowers perfect, the tube short, the limb elongated, 5-toothed. Anthers entire, or minutely 2-toothed at the base. Style-branches tipped with small hirsute appendages. Achenes thick, obtusely 3-4-angled, the summit truncate. Pappus none, or of 2-4 teeth, or a coroniform border. [Greek, sun-like.]
About 6 species, natives of America. Besides the following, two others occur in the southern and southwestern United States. Type species: Heliopsis laevis Pers.
Leaves mostly smooth, or nearly so; pappus none, or of 2-4 stout teeth.
1. H. helianthoides.
Leaves rough; pappus crown-like, or of 1-3 sharp teeth.
2. H. scabra.
Buphthalmum helianthoides L. Sp. Pl. 904. 1753. Heliopsis iaevis Pers. Syn. 2: 473. 1807. Heliopsis helianthoides Sweet, Hort. Brit. 487. 1827.
Stem glabrous, branched above, 3°-5° high. Leaves opposite, or rarely in 3's, ovate or ovate-lanceolate, rather thin, acuminate at the apex, usually abruptly narrowed at the base, sharply and nearly equally dentate, smooth on both sides, or roughish, 3'-6' long, 1'-21/2' wide; heads long-peduncled, somewhat corymbose, 1 1/2'-2 1/2' broad; rays 9'-12" long, persistent, or at length decaying away from the achenes; bracts of the involucre oblong or linear-oblong, obtuse or acutish, the outer commonly longer than the inner; achenes glabrous, the summit truncate; pappus none, or of 2-4 short teeth.
In open places, Ontario to New York, Florida, North Dakota, Illinois and Tennessee. July-Sept.
Heliopsis scabra Dunal, Mem. Mus. Paris 5: 56. pl. 4.
1819. Heliopsis laevis var. scabra T. & G. Fl. N. A. 2: 303.
Similar to the preceding species, but stem rough, at least above, simple or branched, 2°-4° high. Leaves ovate or ovate-lanceolate, acute or sometimes acuminate, sharply dentate, rough on both sides, firm, 2'-5' long, 1 1/2'-2' wide, abruptly narrowed at the base, short-petioled; heads few, or sometimes solitary, long-peduncled, 2'-21/2' broad; rays usually 1' long, or more; bracts of the involucre canescent, oblong or linear-oblong; achenes pubescent on the margins when young; pappus a short laciniate crown, or 1-3 sharp teeth.
Usually in dry soil, Maine to New York, New Jersey, Manitoba, British Columbia. Arkansas and New Mexico. June-Sept. False sunflower.