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..
Helianthus divaricatus L. Sp. PL 906. 1753.
Perennial by slender rootstocks; stem glabrous throughout, or pubescent at the summit, slender, 2°-7° high. Leaves usually all opposite, divaricate, lanceolate or ovate-lanceolate, firm, dentate or denticulate, 3-nerved, rough above, pubescent beneath, sessile or nearly so by a truncate base, tapering gradually to the long-acuminate apex, 3'-8' long, 1/4' - 1 1/2" wide; heads few or solitary, about 2' broad, borne on strigose-pubescent peduncles; involucre hemispheric, its bracts lanceolate or ovate-lanceolate, strigose or hirsute, the outer ones spreading; disk yellow; rays 8-15; chaff of the receptacle apiculate; achenes glabrous; pappus of 2 short subulate awns.
In dry woodlands, Maine and Ontario to Manitoba, Nebraska, Florida and Louisiana. July-Sept.
•Helianthus mollis Lam. Encycl. 3: 85. 1789.
Perennial; stem stout, simple or sparingly branched above, densely hirsute, 2°-4° high. Leaves -ovate or ovate-lanceolate,, closely sessile and somewhat clasping by a broad cordate base, pinnately veined, 3-nerved above the base, all opposite, or the upper alternate, ascending, acute or acuminate, scabrous or cinereous-pubescent above, densely and finely pubescent beneath, serrulate,2-5' long, 1'-21/2' wide; heads solitary or few, 2'-3' broad; involucre hemispheric, its bracts lanceolate, acuminate, densely villous-ca-nescent, somewhat spreading; disk yellow; rays 15-25; chaff canescent at" the summit; mature achenes nearly glabrous; pappus of 2 lanceolate scales.
In dry barren soil, Massachusetts to New Jersey, Georgia, Iowa, Missouri, Kansas and Texas. Aug.-Sept.
Helianthus doronicoides Lam. Encycl. 3: 84. 1789.
Perennial by slender rootstocks; stems stout, rough, or finely rough-pubescent, branched above, 3°-7° high. Leaves oblong, ovate-oblong, or ovate, thick, ascending, serrate or serrulate, acute or acuminate at the apex, narrowed at or below the middle to a sessile or slightly clasping base, rough on both sides, or finely pubescent beneath, 3-nerved, 4'-8' long, i'-2i' wide; heads commonly numerous, 21/2'-4' broad; involucre hemispheric, its bracts lanceolate, acuminate, pubescent or hirsute, somewhat spreading; disk yellow; rays 12-20, 4"-6" wide; achenes glabrous; pappus of 2 subulate awns.
In dry soil, Ohio to Missouri and Arkansas. Recorded from Michigan. Aug.-Sept.
Hleianthus decapetalus L. Sp. Pl. 905. 1753.
Perennial by branched, sometimes thickened root-stocks; stem slender, glabrous or nearly so, branched above, 1°-5° high; branches puberulent. Leaves thin or membranous, 3'-8' long, 1'-3' wide, ovate or ovate-lanceolate, the lower all opposite and slender-petioled, the upper commonly alternate, all usually sharply serrate, roughish above, finely but often sparingly pubescent beneath, acuminate, the rounded or truncate base decurrent on the petiole; heads numerous, 2'-3' broad; involucre hemispheric, its bracts linear-lanceolate, acuminate, hirsute, long-ciliate, spreading, often longer than the yellow disk; rays 8-15, light yellow; chaff entire or 3-toothed, pubescent at the apex; achenes glabrous; pappus of 2 subulate awns.
In moist woods and along streams, Quebec to Michigan, Georgia, Tennessee and Missouri. Aug.-Sept.
Helianthus scrophulariaefdlius Britton, from near Woodlawn, New York, differing by laciniate-serrate leaves, is probably a race of this species.