GENUS 66. 



THISTLE FAMILY 



21. Helianthus tracheliifolius Mill. Throatwort 

 Sunflower. Fig. 4481. 



Helianthus tracheliifolius Mill. Card. Diet. Ed. 8, No. 7. 

 1768. 



Similar to the following species, but the stem usually 

 roughish-pubescent above. Leaves short-petioled, ovate- 

 lanceolate, or lanceolate, 3-nerved, green both sides, but 

 darker above, generally rougher on the upper surface, 

 the lower ones sharply serrate ; branches and peduncles 

 scabrous; heads several, 2i'-3i' broad; bracts of the 

 hemispheric involucre linear-lanceolate, long-acuminate, 

 ciliate and puberulent, longer than the yellow disk, 

 sometimes foliaceous, and 3 times its length. 



In dry soil, Connecticut to Pennsylvania, North Carolina, 

 Ohio, Minnesota and Arkansas. Aug.-Sept. 



22. Helianthus strumosus L. Pale-leaved 

 Wood Sunflower. Fig. 4482. 



Helianthus strumosus L. Sp. PI. 905. 1753. 



H. mollis Willd. Sp. PI. 3 : 2240. 1804. Not Lam. 1789. 



H. macrophyllus Willd. Hort. Berol. pi. 70. 1806. 



Perennial by branched, sometimes tuberous-thick- 

 ened rootstocks ; stem glabrous below, sometimes 

 glaucous, 3-7 high, branched above, the branches 

 usually pubescent. Leaves short-petioled, ovate or 

 ovate-lanceolate, rarely lanceolate, not membranous, 

 rough above, pale and somewhat puberulent or ca- 

 nescent beneath, serrate, serrulate, or nearly entire, 

 acuminate, contracted much below the middle and 

 decurrent on the petiole, 3-nerved above the base, 

 3'-8' long, \'-2.\' wide, mostly opposite, the upper 

 often alternate; heads commonly several, 2^-4' 

 broad; involucre hemispheric, its bracts lanceolate 

 or ovate-lanceolate, acuminate, ciliate, equalling or 

 a little longer than the diameter of the yellow disk; 

 rays 5-15 ; chaff pubescent ; achenes nearly glabrous. 



In dry woods and on banks, Maine and Ontario to 

 Minnesota, Georgia, Tennessee and Arkansas. July- 

 Sept. Races differ in leaf-form and texture. A hybrid 

 with H. decapetalus has been described. 



23. Helianthus hirsutus Raf. Stiff-haired 

 Sunflower. Fig. 4483. 



Helianthus hirsutus Raf. Ann. Nat. 14. 1820. 

 Helianthus hirsutus trachyphyllus T. & G. Fl. N. A. 2 : 

 329. 1842. 



Perennial; stem densely hirsute, usually branched 

 above, stout, rigid, 2-4 high. Leaves ovate-lanceo- 

 late or the upper lanceolate, rounded, truncate or 

 subcordate at the base, acuminate at the apex, thick, 

 very rough above, rough-pubescent beneath, 3-nerved, 

 serrate or serrulate, 3'-6' long, $'-2' wide, short- 

 petioled, or the uppermost sessile, nearly all oppo- 

 site, the petioles of the lower ones \'-\' long; heads 

 usually several, 2'-3i' broad ; involucre hemispheric, 

 its bracts lanceolate, or ovate-lanceolate, acuminate, 

 ciliate, mostly puberulent, erect or somewhat spread- 

 ing, equalling or shorter than the yellow disk ; rays 

 12-15; chaff obtusish, pubescent at the summit; 

 achenes oval, rounded at the summit, glabrous; 

 pappus of I or 2 subulate awns. 



In dry soil, Pennsylvania and Ohio to Wisconsin, Ne- 

 braska, West Virginia, Georgia and Texas. July-Oct. 



