Genus 64.] 



THISTLE FAMILY. 



423 



1803. 



4. Helianthus petiolaris Nutt. Prairie 

 Sunflower. (Fig. 3901.) 



H. petiolaris Nutt. Journ. Acad. Phila. 2: 115. 1821. 



Annual, similar to the preceding species, but smaller 

 and with smaller heads; stem strigose-hispid or hir- 

 sute, i-3 high. Leaves all but the lowest alternate, 

 petioled, oblong, ovate, or ovate-lanceolate, rough on 

 both sides, usually paler beneath than above, \'-t/ 

 long, entire, or denticulate, obtuse or acutish at the 

 apex, mostly narrowed at the base; heads i}4 / -3 / 

 broad; disk brown; involucre depressed-hemispheric, 

 its bracts lanceolate or oblong-lanceolate, densely 

 canescent, not hispid-ciliate, acute or short-acuminate; 

 achenes villous pubescent, at least when young. 



On dry prairies, Minnesota to the Northwest Territory, 

 and Oregon, south to Missouri, Texas and Arizona. Found 

 rarely in waste places farther east. June-Sept. 

 Helianthus petiolaris canus Britton, Mem. Torr. Club, 5: 

 334. 1894. 

 H. petiolaris var. canescens A. Gray, Pi. Wright. 1: 108. 1852. Not H. canescens Michx. 

 Leaves ovate, white-canescent beneath. Nebraska to Texas and New Mexico. 



Helianthus petiolaris patens (Lehni. ) Rydberg, Mem. Torr. Club, 5: 334. 1894. 

 Helianthus patens Lehm. Ind. Sem. Hamburg. 1828. 



Heads larger, long-peduncled, the peduncles fleshy toward the top; leaves large, long-petioled. 

 Nebraska. 



5. Helianthus atrorubens L. Hairy Wood Sunflower. Purple-disk 



Sunflower. (Fig. 3902.) 



Helianthus atrorubens L,. Sp. PI. 906. 1753- 



Perennial; stems hirsute below, often minutely pu- 

 bescent above, branched at the summit, 2-5 high. 

 Leaves hirsute on both sides, or canescent beneath, 

 mostly thin, ovate or ovate-lanceolate, acutish, con- 

 tracted near the base into margined petioles, dentate or 

 crenate-dentate, 4 / -io / long,i / -4 / wide, the lower op- 

 posite, the upper few, distant, small, mainly alternate; 

 heads not numerous, slender-peduncled, about 2 / 

 broad; involucre hemispheric, its bracts oblong to ob- 

 ovate, obtuse, ciliolate, appressed; disk purple; recep- 

 tacle convex, its chaff acute, entire, or 3-toothed; rays 

 10-20; achenes obovate, truncate, finely pubescent, 

 about 2" long; pappus usually of 2 lanceolate awns. 

 In dry woods, Virginia to Florida, west to Ohio, Miss- 

 ouri, Arkansas and Louisiana. Aug.-Oct. 



6. Helianthus scaberrimus Ell. Stiff 

 Sunflower. (Fig. 3903.) 



H. scaberrimus Ell. Bot. S, C. & Ga. 2: 423. 1824. 

 H. rigidus Desf. Cat. Hort. Paris, Ed. 3, 1S4. 1829. 



Perennial; stems simple or little branched, hispid 

 or scabrate, i-8 high. Leaves thick, coriaceous, 



serrate or serrulate, very scabrous on both sides, 1'- 

 7' long, )/ 2 '-2' wide, acute at the apex, narrowed at 

 the base, the lower ovate or ovate oblong, petioled, 

 the upper lanceolate or oblong-lanceolate, sessile or 

 short-petioled, all opposite, or the uppermost bract- 

 like and alternate; heads solitary or few, 2 / -3 / broad; 

 involucre hemispheric, its bracts ovate, acute or ob- 

 tusish, ciliate; disk purple or brown; receptacle con- 

 vex, its chaff obtuse; rays 15-25, light yellow; achenes 

 more or less pubescent, oblong-obovate; pappus of 2 

 broad scales or of 2-4 stout awns. 



Prairies, Minnesota to the Northwest Territory, south 

 to Illinois, Georgia, Texas and Colorado. Aug. -Sept. 



