Genus 66. 



THISTLE FAMILY. 



3. Helianthus angustifolius L. Xarrow-leaved 

 or Swamp Sunflower. Fig. 4463. 



Helianthus angustifolius L. Sp. PI. 906. 1753. 



Perennial by slender rootstocks ; stems branched above, 

 or simple, slender, rough or roughish above, often hir- 

 sute below, 2-J high. Leaves firm, entire, sessile, 

 linear, slightly scabrous, rarely somewhat canescent be- 

 neath, 2'-f long, 2"~3" wide, the margins revolute when 

 dry, the upper ones all alternate, the lower opposite ; 

 heads usually few, sometimes solitary, 2'-$' broad; in- 

 volucre hemispheric, its bracts linear-lanceolate, acute 

 or acuminate, scarcely squarrose, pubescent; receptacle 

 slightly convex; disk purple; chaff entire or 3-toothed ; 

 rays 12-20; achenes truncate, glabrous; pappus usually 

 of 2 short awns.- 



In swamps. Long Island, N. Y., to Florida, Kentucky and 

 Texas, mainly near the coast. Aug.-Oct. 



4. Helianthus orgyalis DC. Linear-leaved 

 Sunflower. Fig. 4464. 



H. giganteus var. crinitus Nutt. Gen. 2: 177. 1818? 

 Helianthus orgyalis DC. Prodr. 5: 586. 1836. 



Perennial by slender rootstocks ; stems glabrous, 

 branched near the summit, very leafy to the top, 

 6-io high. Leaves sessile, entire, linear or nearly 

 filiform, or the lowest lanceolate, remotely dentate 

 and short-petioled, rough with mucronate-tipped 

 papillae, especially on the lower surface, acuminate, 

 4/-16' long, i"--l" wide, the upper all alternate and 

 i-nerved, the lower commonly opposite ; heads nu- 

 merous, about 2 broad, terminating slender branches ; 

 involucre nearly hemispheric, its bracts linear-subu- 

 late to lanceolate, acuminate, squarrose, ciliate ; disk 

 purple or brown ; receptacle convex, its chaff entire, 

 or toothed, slightly ciliate; rays 10-20; achenes ob- 

 long-obovate, glabrous, 2j"-3" long, 2-4-awned. 



On dry plains. Missouri and Nebraska to Colorado 

 and Texas. Sept.-Oct. 



5. Helianthus atrorubens L. 



Hairy Wood Sunflower. 

 Fig. 4465. 



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



Perennial ; stems hirsute below, often minutely pu- 

 bescent above, branched at the summit, 2-$" high. 

 Leaves hirsute on both sides, or canescent beneath, 

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

 tracted near the base into margined petioles, sometimes 

 subcordate, dentate or crenate-dentate, 4'-io' long, l'-4' 

 wide, the lower opposite, the upper few, distant, small, 

 mainly alternate; heads not numerous, slender-pedun- 

 cled, about 2' broad ; involucre hemispheric, its bracts 

 oblong to obovate, obtuse, ciliolate, appressed ; disk 

 purple; recptacle convex, its chaff acute, entire, or 

 3-toothed; rays 10-20; achenes obovate, truncate, finely 

 pubescent, about 2" long; pappus usually of 2 lanceo- 

 late awns. 



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

 souri, Arkansas and Louisiana. Aug.-Oct. 



Purple-disk Sunflower. 



