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 or annual herbs or shrubs with alternate spinulose-dentate or lobed leaves and many-flowered heads of tubular or of both tubular and radiate yellow flowers (heads rarely without rays). Involucre hemispheric to campanulate, its bracts imbricated in several series, the outer ones gradually smaller. Receptacle flat or convex, generally foveolate, naked. Ray-flowers fertile. Disk-flowers usually perfect. Anthers obtuse and entire at the base. Style-branches flattened, their appendages short, lanceolate. Achenes oblong or obovoid, obtuse, white-tomentose, or canescent, usually 8-10-nerved. Pappus of 1-3 series of numerous capillary persistent more or less unequal bristles. [Greek, iron-flower.]
About 15 species, natives of America. Besides the following, about 10 others occur in the western parts of the United States. Type species: Sideranthus spinulosus (Nutt.) Sweet.
Rays none; leaves dentate.
1. S. grindelioides.
Leaves dentate; annual.
2. S. annuus.
Leaves pinnatifid; perennial.
3. S. spinulosus.
Eriocarpum grindelioides Nutt. Trans. Am. Phil. Soc. (II.) 7: 321. 1841.
Aplopappus Nuttallii T. & G. Fl. N. A. 2: 240. 1842.
Sideranthus grindelioides Britton, Manual 932. 1901.
Perennial by a deep woody root, finely pubescent; stems tufted, simple, erect, 4'-12' high. Leaves oblong-lanceolate to spatulate, sessile, or the lower peti-oled, 1/2'-1' long, firm, acute or obtusish, spinulose-dentate; heads several or solitary, terminating the stem or branches; peduncles 1' long, or less; involucre campanulate, its bracts linear, acute, puberulent, their tips somewhat spreading, the outer shorter than the inner; achenes densely silky tomentose.
In dry soil, South Dakota to Assiniboia, Nebraska, New Mexico and Arizona. July-Aug.
653. 1904. Aplopappus rubiginosus A. Gray, Syn. Fl. 12: 130.
1884. Not T. & G.
Viscid, glandular-pubescent, erect, annual, branched near the summit, 1°-3° high. Leaves sessile, or the lowest narrowed into short petioles, oblong, lanceolate, or oblanceolate, conspicuously dentate with distant awn-pointed teeth, acute or obtusish at the apex. 11/2'-21/2' long, 2"-6" wide; heads several, cymose-paniculate, 8"-15" broad; involucre hemispheric, its bracts linear-subulate with spreading tips; rays large; pappus bristles rigid, very unequal; achenes villous-canescent, turbinate, not compressed.
On plains and in canons, Nebraska, Kansas and Colorado. Erroneously referred in our first edition to Eriocarpum rubiginosum. Aug.-Sept.
Amellus spinulosus Pursh, Fl. Am. Sept. 2: 564.
1814. Sideranthus spinulosus Sweet, Hort. Brit. 227.
1894. S. glaberrimus Rydb. Bull. Torr. Club 27: 621.
Canescent or glabrate, much branched at the base, perennial by thick woody roots, 6'-15' high. Leaves pinnatifid, sessile, linear to ovate in outline, 1/2'-1 1/2' long, 1"-21/2" wide, the lobes with bristle-poirtfed teeth; heads several or numerous (rarely solitary), 6"-12" broad; involucre hemispheric, its bracts linear, acute, ap-pressed; rays narrow; achenes pubescent, narrowed below; pappus soft and capillary.
In dry soil, Minnesota and North Dakota to Saskatchewan, Alberta, Colorado, Nebraska, Texas and Mexico. March-Sept.