GENUS 66. 



THISTLE FAMILY 



9. Helianthus laevigatus T. & G. Smooth 



Sunflower. Fig. 4469. 

 Helianthus laevigatus T. & G. Fl. N. A. 2 : 330. 1842. 



Stems slender, from a perennial root, simple or 

 little branched, glabrous, or somewhat glaucous, 

 2-6 high. Leaves nearly all opposite, firm, gla- 

 brous, lanceolate, short-petioled, or. the upper sessile, 

 serrulate or entire, pale beneath, acuminate, nar- 

 nowed at the base, s'-6' long, A'-ii' wide, the mar- 

 gins sometimes roughish-ciliate ; heads few or soli- 

 tary, i'-ii' broad; involucre campanulate, its bracts 

 lanceolate or ovate-lanceolate, firm, ciliolate, the 

 tips of the outer ones spreading; rays 5-10; disk 

 yellow ; chaff linear ; achenes slightly pubescent at 

 the summit ; pappus of 2 lanceolate or ovate owns, 

 with or without 2 intermediate scales. 



In dry soil, mountains of Virginia, West Virginia 

 and North Carolina. Aug.-Oct. 



10. Helianthus microcephalus T. & G. 

 Small Wood Sunflower. Fig. 4470. 



Helian'hus parviflorus Bernh. ; Spreng. Syst. 3: 617. 



1826. Not H.B.K. 1820. 

 H. microcephalus T. & G. Fl. N. A. 2 : 329. 1842. 



Stems slender, glabrous, branched above, or 

 rarely simple, 3-6 high. Leaves thin or thin- 

 nish, petioled, most of them opposite, lanceolate, 

 or the lower ovate-lanceolate, rough above, canes- 

 cent or puberulent beneath, long-acuminate at the 

 apex, narrowed at the base, serrulate, or the 

 lower serrate, 3'-?' long, i'-ii' wide; heads com- 

 monly several or numerous, i'-ii' wide, borne 

 on slender, sometimes roughish peduncles ; invo- 

 lucre campanulate, 4"-5" broad, its bracts lanceo- 

 late or ovate, acute or acuminate, ciliolate, the 

 tips of the outer ones spreading; chaff of the 

 receptacle oblong, entire, or 3-toothed; rays 5-10; 

 disk yellow; achenes nearly glabrous; pappus 

 usually of 2 subulate awns. 



In moist woods and along streams, Pennsylvania to 

 Georgia, west to Ohio, Missouri and Louisiana. July- 

 Sept. 



ii. Helianthus giganteus L. Tall, Giant or 

 Wild Sunflower. Fig. 4471. 



Helianthus giganteus L. Sp. PI. 905. 1753. 



Perennial by fleshy roots and creeping rootstocks ; 

 stems hispid or scabrous, at least above, branched near 

 the summit, or simple, 3-i2 high. Leaves sessile or 

 short-petioled, firm, lanceolate, very rough above, 

 rough-pubescent beneath, serrate or denticulate, acumi- 

 nate at the apex, narrowed at the base, many or all of 

 the upper ones alternate but sometimes all opposite, 

 2'-6' long, i'-i' wide ; heads usually several, mostly 

 long-peduncled, ii'-2j' broad; involucre hemispheric, 

 its bracts squarrose, lanceolate-subulate, hirsute or 

 ciliate, commonly as long as the diameter of the yel- 

 lowish disk; chaff of the receptacle oblong-linear, 

 acute; achenes oblong, glabrous; rays 10-20; pappus 

 of 2 subulate awns. 



In swamps and wet meadows, Maine and Ontario to Sas- 

 katchewan, Florida, Louisiana and Colorado. Stem com- 

 monly purple. Aug.-Oct. 



Helianthus ambiguus (A. Gray) Britton, differing in 

 having all but the uppermost leaves opposite and rounded 

 at the base, found on Long Island, New York, and recorded 

 from Georgia, appears to be a hybrid, with this species one of its 



31 



parents. 



