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..
Rough-hairy annual or biennial herbs, loosely paniculately branched, with alternate linear to lanceolate, 1-nerved, entire or somewhat toothed leaves, and small slender-peduncled heads of radiate and tubular yellow flowers. Involucre campanulate-cylindric, its appressed lanceolate or subulate bracts in 2 or 3 series. Receptacle alveolate. Ray-flowers 5-12, pistillate. Disk-flowers 10-20, perfect. Anthers not sagittate. Style-appendages narrow, hirsute. Achenes terete, narrowed below, silky-villous. Pappus a single series of rough capillary bristles, nearly equal in length. [Greek, equal-pappus.]
Two known species, natives of the southern United States, the following typical.
Inula divaricata Nutt. Gen. 2: 152. 1818.
Aplopappus divaricatus A. Gray, Syn. Fl. 1: Part 2, 130. 1884.
Isopappus divaricatus T. & G. Fl. N. A. 2: 239. 1841.
Annual or biennial, erect, paniculately much branched, slender, rough-pubescent or glandular, 1°-3° high. Leaves linear, linear-lanceolate, or the lowest linear-spatulate, acute or cuspidate, dentate with distant teeth, or somet'mes entire, 1' -3 ' long, 1"-3" wide, the uppermost much smaller, subulate or bract-like; heads numerous, 3"-5" broad; involucre campanulate, its bracts linear-lanceolate, subulate-tipped, pubescent, peduncles very slender, or filiform.
In dry soil, Kansas to Texas, east to Georgia and Florida. Aug.-Oct.