378 . COMPOSITAE. Vor. III. 
19. SIDERANTHUS Fraser, Cat. 1813; Sweet, Hort. Brit. 227. 1826. 
[Errocarpum Nutt. Trans. Am. Phil. Soc. (II) 7: 320. 1841.] 
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 numer- 
ous 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. 
Rays present. 
Leaves dentate; annual. 2. S. annuus. 
Leaves pinnatifid ; perennial. 3. S. spinulosus. 
1. Sideranthus grindelioides (Nutt.) Britton. 
Rayless Sideranthus. Fig. 4208. 
Eriocarpum grindelioides Nutt. Trans. Am: Phil. Soc. 
IL.) 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 ob- 
long-lanceolate to spatulate, sessile, or the lower peti- 
oled, 4’-1’ long, firm, acute or obtusish, spinulose- 
dentate; heads several or solitary, terminating the 
stem or branches; peduncles 1’ long, or less; invo- 
lucre 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. 
2. Sideranthus 4nnuus Rydb. Viscid 
Sideranthus. Fig. 4209. 
Sideranthus annuus Rydb. Bull. Torr. Club 31: 
653. 1904. fe 
Aplopappus rubiginosus A. Gray, Syn. Fl. 17: 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-point- 
ed teeth, acute or obtusish at the apex, 14’-23’ 
long, 2”-6” wide; heads several, cymose- 
paniculate, 8’-15” broad; involucre hemi- 
spheric, its bracts linear-subulate with spread- 
ing 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 N 
edition to Eriocarpum rubiginosum, Aug.—Sept. 
